Single-use external dosimeters for use in radiation therapies and related methods, systems and computer program products

ABSTRACT

Methods, systems, devices, and computer program products include positioning disposable single-use radiation sensor patches that have adhesive means onto the skin of a patient to evaluate the radiation dose delivered during a treatment session. The sensor patches are configured to be minimally obtrusive and operate without the use of externally extending power chords or lead wires.

RELATED APPLICATIONS

[0001] This application is a continuation in part of and claims priorityfrom U.S. patent application Ser. No. 10/303,591 entitled DisposableSingle-Use External Dosimeters For Use in Radiation Therapies, filedNov. 25, 2002, which claims priority from U.S. Provisional PatentApplication Serial No. 60/334,580 entitled Disposable Single-UseExternal Dosimeters for Use in Radiation Therapies, filed Nov. 30, 2001,the contents of which are hereby incorporated herein by reference as ifset forth in their entirety.

FIELD OF THE INVENTION

[0002] The present invention generally relates to the assessment orquantitative evaluation of the amount of radiation delivered to apatient receiving radiation during a therapeutic procedure.

RESERVATION OF COPYRIGHT

[0003] A portion of the disclosure of this patent document containsmaterial to which a claim of copyright protection is made. The copyrightowner has no objection to the facsimile reproduction by anyone of thepatent document or the patent disclosure, as it appears in the Patentand Trademark Office patent file or records, but reserves all otherrights whatsoever.

BACKGROUND OF THE INVENTION

[0004] Conventionally, radiation therapy is delivered over a successiveseries of radiation treatment sessions. High-energy photons and/orelectrons are carefully directed and/or focused from an ex vivoradiation source so that they travel into a targeted treatment area in apatient's body. The size, shape, and position of the treatment area(typically where a tumor is or was) as well as its anatomical locationin the body and its proximity to sensitive normal tissues are consideredwhen generating a particular patient's treatment plan. That is, thetreatment is planned so as to deliver a suitably high dose of radiationto the tumor or targeted tissue while minimizing the dose to nearbysensitive tissue that typically cannot be completely avoided. Directingradiation into non-affected regions may produce undesired side effectsparticularly as it relates to tissue that may be sensitive to certaindosages of radiation. Unfortunately, even when the patient plan iscarefully constructed to account for the location of the canceroustissue and the sensitive non-affected regions, even small errors inset-up due to beam angle or patient position during delivery of theradiation therapy can inadvertently misdirect radiation into thoseregions or can influence the dose amount that is actually received bythe targeted tissue. Further, the demand for radiation treatmentequipment is typically relatively high and this demand may limit theset-up time allowed or allocated in the treatment room between patients.

[0005] In the past, implantable devices for oncology applications havebeen proposed to evaluate the radiation dose amount received in vivo atthe tumor site. See e.g., U.S. Pat. No. 6,402,689 to Scarantino et al.,the contents of which are hereby incorporated by reference herein.Measuring the radiation at the tumor site in vivo can provide improvedestimates of doses received. However, for certain tumor types orsituations, a skin-mounted or external surface radiation dosimeter maybe desirable and sufficient for clinical purposes.

[0006] Conventional external or skin-mounted radiation dosimeter systemsuse semiconductor circuitry and lead wires that power/operate thedosimeters. These types of dosimeters are available from Scandatronicsand/or IBA (“Ion Beam Applications”) having an internationalheadquarters location in Belgium. While these radiation dosimetersystems may provide radiation dose estimations, they can, unfortunately,be relatively expensive. Further, these types of dosimeters are used fora plurality of patients potentially raising sterility or cleanlinessproblems between patients. Conventional dosimeter systems may alsorequire substantial technician time before and during the radiationsession. For example, conventional dosimeter systems need to becalibrated before the radiation session may begin. In addition, the leadwires can be cumbersome to connect to the patients and may requireexcessive set-up time as the technician has to connect the lead wires torun from the patient to the monitoring system and then store the leadwire bundle between patient treatment sessions. Therefore, techniciansdo not always take the time to use this type of system, and noconfirmation estimate of the actual radiation delivered is obtained.

[0007] Other radiation sensors include thermo-luminescent detectors(TLD's). However, while TLD detectors do not require wires duringoperation, they are analyzed using a spectrophotometer (that may belocated in an offsite laboratory) and are not conducive to real-timereadings.

[0008] Devices, methods and systems of radiation detection are alsodiscussed in U.S. Pat. Nos. 4,678,916, 5,117,113, 5,444,254, 6,172,368,6,614,025 and 6,650,930 that are assigned to Thomson & Nielsen.

[0009] In view of the foregoing there remains a need for improvedeconomical and easy to use radiation dosimeters.

OBJECTS AND SUMMARY OF THE INVENTION

[0010] It is therefore an object of the present invention to provide acost-effective surface mount radiation dosimeter that can be used toevaluate the radiation dose delivered to a patient undergoing radiationtherapy.

[0011] It is a further object of the present invention to provideeconomic methods and devices that can reduce labor set-up time in theradiation treatment chamber over conventional evaluation methods anddevices.

[0012] It is an additional object of the present invention to provide amemory storage device on the patch to record the dose history of thepatch. This memory storage device may be queried at any time in order toobtain a record of the dose applied to the patch. Other information,such as patient identification, time, date, hospital, therapist, stateof the device, dosed/undosed and calibration data may be stored in thememory storage device.

[0013] It is an additional object of the present invention to provide aneconomic method of determining the amount of radiation delivered to anoncology patient in situ.

[0014] These and other objects can be satisfied by the present inventionby a disposable, single-use skin mounted radiation dosimeter that has aself-contained package that is small, adhesively attachable to the skinof the patient, and operates in a relatively easy to operate and readmanner without requiring the use of lead wires.

[0015] Certain embodiments of the present invention are directed tomethods for monitoring radiation doses administered to patientsundergoing radiation treatments. The methods include the steps of: (a)releasably securing at least one single-use dosimeter sensor patch ontothe skin of the patient such that the patch is self-contained and devoidof leads extending therefrom; (b) administering radiation to the patientin a first treatment session; (c) contacting the sensor patch with adose-reader device after the administering step to obtain dataassociated with a change in an operational parameter in the dosimetersensor patch; and (d) determining the radiation dose received by thepatient during the administering step based on the change in theoperational parameter.

[0016] In some embodiments, the sensor patch may be pre-dosed and/orcalibrated before the sensor patch is secured to the patient. Theobtained data may be stored in an electronic storage device provided onthe sensor patch itself. The storage device may be, for example, anEEPROM. Other information, such as the patient's name, the doctor'sname, the test date and the like, may also be stored in the storagedevice provided on the sensor patch. In further embodiments of thepresent invention, the electronic memory may include methodology datathat instructs a reader how to interface with, i.e., obtain data from,the sensor patch(es). In still further embodiments of the presentinvention, the electronic memory may include a zero temperaturecoefficient (which may be used interchangeably for the phrase “zerotemperature coefficient”) of a MOSFET included on the sensor patch. Thiszero temperature coefficient may be used to bias the MOSFET after theradiation treatment before a post-radiation threshold voltage isobtained. Alternatively, the data can be stored on a computer readablememory integrated on a physical record sheet that can be placed in thepatient's file.

[0017] In some embodiments of the present invention, a zero temperaturecoefficient of the MOSFET may be measured prior to the administering oftherapeutic radiation to the patient and stored in the electronicmemory. The MOSFET may be biased using the stored zero temperaturecoefficient after the administration of therapeutic radiation to thepatient and the radiation dose may be automatically calculated based onthe change in threshold voltage of the MOSFET.

[0018] Other embodiments are directed to systems for monitoringradiation administered to a patient during a therapeutic treatment. Thesystem comprises: (a) at least one disposable single-use dosimeterpatch, the patch comprising a body holding a circuit with at least oneMOSFET and an external reader contact region thereon, the MOSFET(s)having an associated threshold voltage that changes when exposed toradiation, the body comprising opposing upper and lower primarysurfaces; and (b) an external portable dose-reader being configured tomake electrical contact with the patch by physically engaging with thecontact region on the patch to obtain voltage threshold datacorresponding to the dose amount of radiation exposure it is exposed toin use. During irradiation, the patch is self-contained (e.g., has aperimeter that is devoid of outwardly external lead wires).

[0019] In some embodiments, the patch includes a conformable resilientbody. The lower primary surface may include a medical grade adhesive andthe sensor patch may be pressed on to secure the sensor patch to thepatient. In other embodiments, an adhesive coverlay is applied over thesensor patch to secure the sensor to the patient. A portion or all ofthe sensor patch may be adapted to be inserted into the dose-reader totransmit the dose data and the dose-reader may similarly be adapted toreceive a portion or all of the sensor patch. Insertion of the sensorpatch into the reader electrically couples the sensor to the reader andallows the reader to receive the radiation dose data from the sensorpatch. The sensor patch may also include an electronic storage device inelectrical communication with the sensor. The sensor patch may then bepre-dosed and/or calibrated before the radiation session. Data may bedownloaded from the electronic memory of the sensor patch to a remotecomputer and/or a computer application using the electrical coupling ofthe sensor patch and the dose-reader.

[0020] In certain embodiments, the at least one dosimeter patch is aplurality of discrete sensor patches and the reader is configured toserially contact with each respective sensor patch to obtain thethreshold voltage value associated therewith.

[0021] A sheet of sensor patches may be pre-dosed and/or calibratedsimultaneously or individually before the sensor patches are secured tothe patient. The calibration and/or pre-dosing may be performed at theoriginal equipment manufacturer (OEM) or at the actual test site. Thesheet of sensor patches may include about 30 to about 100 sensors. Thesensors may also be provided in a high density array of sensors where somany sensors are provided in a certain area of the high density array,for example, multiple sensors may be provided per square inch or per 3by 3 inch regions of the high density array.

[0022] Still other embodiments are directed to sets of disposablesingle-use radiation dosimeter patches. The sets comprise a plurality ofdiscrete disposable single-use dosimeter patches, each patch comprises aconformable body holding a circuit with an operational electroniccomponent that changes a parameter in a detectable predictable mannerwhen exposed to radiation, the body comprising opposing upper and lowerprimary surfaces and the dosimeter patch, in use and positioned on thepatient, is devoid of externally hanging lead wires.

[0023] The operational electronic component may be a radiation sensitivebiased MOSFET or MOSFETs (such as MOSFET pairs) and the detectableoperational parameter that changes can be the MOSFET thresholdvoltage(s). Furthermore, a medical grade adhesive may be supplied on thelower primary surface of the sensor body such that the sensor may beadhered to the patient's skin. In certain embodiments, an adhesivecoverlay may be provide over the body of the sensor to secure the sensorto the patients skin.

[0024] In some embodiments of the present invention, a buildup cap isplaced over the sensor patch to, for example, simulate placement of thesensor patch beneath the patient's skin. This type of simulation mayhelp to focus and/or form equilibrium in the radiation beam in proximityto the sensor patch and, therefore, increase the reliability ofradiation measurement. The buildup cap may simulate a distance of fromabout 1 to about 3 cm beneath the skin of the patient. In certainembodiments of the present invention, the buildup cap may have ahemispherical shape and may be configured to hook onto the sensor patch.The buildup cap may include a layer of molded polystyrene and a layer ofcopper on the layer of molded polystyrene. The copper layer may have athickness of from about 0.5 to about 1 mm and the polystyrene may have adiameter of from about 6 to about 7 mm.

[0025] Another embodiment is directed to a computer program product forevaluating a radiation dose delivered to a patient. The computer programproduct comprises a computer readable storage medium having computerreadable program code embodied in the medium. The computer-readableprogram code comprises: (a) computer readable program code for receivingpre-irradiation threshold voltage data associated with a plurality ofdisposable sensor patches; (b) computer readable program code foraccepting data from a reader configured to electrically serially contacteach of the plurality of disposable sensors for a short time; and (c)computer readable program code for determining the voltage thresholdshift of the disposable sensor patches after radiation to determine theradiation exposure.

[0026] In still further embodiments of the present invention, adose-reader may be adapted to receive a sensor patch in a sensor port.The sensor patch is also adapted to be inserted in the sensor port. Thedose-reader can be a pocket or palm sized portable device. Thedose-reader may also include a communications port, for example, auniversal serial port (USB), RS 232 and the like, for downloadingobtained data to a computer application or remote computer. Thedose-reader functionality may be incorporated into a personal digitalassistant (PDA) or other pervasive computer device.

[0027] In some embodiments of the present invention, a dose reader maybe provided having a circuit integrated with the reader that isconfigured to communicate with an electronic memory of at least onesingle use dosimeter patch to obtain threshold data corresponding to adose amount of radiation exposure the at least one sensor patch isexposed to in use and to prompt a user to provide predetermined dataneeded to determine the dose amount. The dose reader may be configuredto automatically prompt the user of the reader for predetermined databefore determining the radiation dose and automatically determine theradiation dose using the predetermined data. The predetermined data mayinclude a correction factor related to the at least one sensor patch.

[0028] In further embodiments the sensor patch may be configured tocommunicate with the dose-reader wirelessly. For example, the sensorpatch and the dose-reader may both be equipped with a radio frequency(RF) interface so that information may be shared between the twodevices.

[0029] In still further embodiments of the present invention, a teststrip may be provided. The test strip is sized and configured to be readby an external dose-reader. The test strip can be sized and configuredto be generally the same as a patch. The test strip may include aconformable substrate holding a circuit. The circuit may include aresistor and a voltage reference, operational parameters of which may beconfigured to change in a detectable predictable manner when exposed toradiation to indicate a calibrated status of the external reader.

[0030] In some embodiments of the present invention, the voltagereference of the test strip includes a 1.2 V shunt and the resistorincludes comprises a 10 KΩ resistor. The circuit may be adapted toengage with the external reader, compare a pre-radiation value to apost-radiation value to provide a comparison result and determine thestate of the reader based on the comparison result. The circuit may beconfigured to indicate that the external reader is functional if thecomparison result is within a set of defined limits and that theexternal reader is not functional if the comparison result is outsidethe set of limits.

[0031] The foregoing and other objects and aspects of the presentinvention are explained further in the specification set forth below.

BRIEF DESCRIPTION OF THE FIGURES

[0032]FIG. 1 is a schematic illustration of a patient undergoingradiation treatment according to some embodiments of the presentinvention.

[0033]FIG. 2 is a block diagram of operations for monitoring patientsundergoing radiation treatments according to further embodiments of thepresent invention.

[0034]FIGS. 3A and 3B are illustrations of sets of disposable dosimeterpatches according to still further embodiments of the present invention.

[0035]FIG. 3C is an anatomical map of sensor location according to someembodiments of the present invention.

[0036]FIG. 4 illustrates an exemplary patient information form accordingto some embodiments of the present invention.

[0037]FIGS. 5A and 5B are schematic illustrations of sensor placement ona patient according to further embodiments of the present invention.

[0038]FIG. 6 is a schematic illustration of embodiments of a readercontacting the sensor to obtain the radiation dosage data according tostill further embodiments of the present invention.

[0039]FIG. 7A is a schematic illustration of further embodiments of areader receiving the sensor in a sensor port to obtain the radiationdosage data according to some embodiments of the present invention.

[0040]FIG. 7B is a schematic illustration of still further embodimentsof a reader receiving wireless communications from the sensor to obtainthe radiation dosage data according to further embodiments of thepresent invention.

[0041]FIG. 8A is a greatly enlarged side view of a disposable radiationdosimeter according to still further embodiments of the presentinvention.

[0042]FIG. 8B is a top view of the dosimeter shown in FIG. 8A.

[0043]FIG. 8C is a partial cutaway view of a probe head for a readeraccording to some embodiments of the present invention.

[0044]FIG. 9A is a schematic of embodiments of a sensor patch with acircuit thereon according to further embodiments of the presentinvention.

[0045]FIG. 9B is a schematic of further embodiments of a sensor patchwith a circuit thereon according to still further embodiments of thepresent invention.

[0046]FIG. 9C is a schematic of further embodiments of a sensor patchwith a circuit thereon according to some embodiments of the presentinvention.

[0047]FIG. 9D is a schematic of further embodiments of a sensor patchaccording to further embodiments of the present invention.

[0048]FIG. 9E is a schematic of further embodiments of a sensor patchaccording to still further embodiments of the present invention.

[0049]FIG. 10A is a schematic illustration of a sheet of sensorsaccording to some embodiments of the present invention.

[0050]FIG. 10B is yet another schematic illustration of a sheet ofsensors according to further embodiments of the present invention.

[0051]FIG. 10C is a further schematic illustration of a sheet of sensorsaccording to still further embodiments of the present invention.

[0052]FIG. 10D is still a further schematic illustration of a sheet ofsensor patches according to some embodiments of the present invention.

[0053]FIG. 11 is a schematic of a circuit diagram of a MOSFET sensorwith a reader interface and an optional memory according to someembodiments of the present invention.

[0054]FIG. 12A is a schematic of a threshold voltage reader circuitaccording to further embodiments of the present invention.

[0055]FIG. 12B is a graph of the change in the threshold voltage valueversus radiation dose according to still further embodiments of thepresent invention.

[0056]FIG. 13 is a graph of the threshold voltage dependence on Idsusing the voltage (V₀) of the reader illustrated in FIG. 12A.

[0057]FIG. 14A is a schematic of a circuit diagram with a MOSFET pair,the left side of the figure corresponding to an irradiation operativeconfiguration and the right side of the figure corresponding to a readdose operative configuration, according to some embodiments of thepresent invention.

[0058]FIG. 14B is a schematic of a circuit diagram with a MOSFET pair,the left side of the figure corresponding to an irradiation operativeconfiguration and the right side of the figure corresponding to a readdose operative configuration, according to further embodiments of thepresent invention.

[0059]FIG. 15A is a schematic of a system or computer program productfor estimating radiation based on data taken from a point contact-readerdata acquisition system according to still further embodiments of thepresent invention.

[0060]FIG. 15B is a block diagram illustrating a reader device accordingto some embodiments of the present invention.

[0061]FIG. 15C is a block diagram illustrating a reader device accordingto further embodiments of the present invention.

[0062]FIG. 16 is a block diagram of a computer program having aradiation estimation module according to still further embodiments ofthe present invention.

[0063]FIG. 17 is a block diagram of a point-contact reader dataacquisition system some according to embodiments of the presentinvention.

[0064]FIGS. 18A and 18B are schematic diagrams illustrating buildup capsaccording to further embodiments of the present invention.

[0065]FIG. 19 is a table including sensor specifications according tofurther embodiments of the present invention.

[0066]FIG. 20 is a block diagram illustrating functions of a readerdevice and a patch according to some embodiments of the presentinvention.

[0067]FIG. 21 is a block diagram illustrating a process for modifyingconversion parameters and bias timing according some embodiments of thepresent invention.

[0068]FIG. 22 is a schematic diagram of a test strip according tofurther embodiments of the present invention.

[0069]FIG. 23 is a calibration curve illustrating a dose response of anexemplary MOSFET/RADFET according to still further embodiments of thepresent invention.

[0070]FIG. 24 is a graph illustrating an exemplary correction factor forenergy dependence according to some embodiments of the presentinvention.

[0071]FIG. 25 is a table illustrating exemplary “k-factors” that may beapplied to a dose equation according to further embodiments of thepresent invention.

[0072]FIG. 26 is a table illustrating an order of storing temperaturecorrection coefficients according to still further embodiments of thepresent invention.

[0073]FIG. 27 is a table illustrating an order of storing fadecorrection coefficient according to some embodiments of the presentinvention.

[0074]FIG. 28 is a graph illustrating an exemplary response for fade inthe RADFET voltage following a dose application according to furtherembodiments of the present invention.

[0075]FIG. 29 is a table including V/I relationships of readersaccording to still further embodiments of the present invention.

[0076]FIG. 30 is a table including a list of items included in anexemplary dose record according to some embodiments of the presentinvention.

[0077]FIG. 31 is a table including functional specifications of teststrips according to further embodiments of the present invention.

[0078]FIG. 32 is a table including functional specifications readersaccording to still further embodiments of the present invention.

[0079]FIG. 33 is a table including functional specifications of patchesaccording to some embodiments of the present invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0080] The present invention will now be described more fullyhereinafter with reference to the accompanying figures, in whichembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Like numbers refer to like elementsthroughout. In the figures, certain components, features, or layers maybe exaggerated for clarity. In the block diagrams or flow charts, brokenlines indicate optional operations, or features unless stated otherwise.As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

[0081] The terminology used herein is for the purpose of describingparticular embodiments only and is not intended to be limiting of theinvention. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

[0082] Unless otherwise defined, all terms (including technical andscientific terms) used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand should not be interpreted in an idealized or overly formal senseunless expressly so defined herein.

[0083] The statements characterizing one or more of the priorityapplications as a “continuation-in-part” application of a priorapplication listed under the “Related Applications” section above isused to indicate that additional subject matter was added to thespecification of the prior application but does not necessarily meanthat the entire invention described and claimed in the presentapplication is not supported in full by the prior application(s).

[0084]FIG. 1 illustrates an example of a radiation system 10 with aradiation beam source 20 directed at a patient 50 having a tumor site.The patient 50 can be positioned so as to be aligned and stationary withrespect to the beam 20 b (illustrated by the diverging dotted lines)during the treatment. As such, the patient 50 can be arranged in anydesired position depending on the direction of the beam, the location ofthe tumor, and the type of radiation therapy system employed. As shown,the patient is reclined, substantially flat and face up on a table sothat the beam 20 b is directed into the targeted tumor site in the bodyas the patient undergoes radiation therapy in a treatment session.Typically, the patient will undergo a plurality of successive treatmentsessions over a treatment period. Each treatment session may be plannedto administer radiation doses of between about 1-2 Gray (100-200 cGy)with an overall typical treatment limit of about 35-80 Gray.

[0085] To help monitor or estimate the amount of radiation that isdelivered to the patient during a treatment session, at least onedisposable single-use dosimeter sensor patch 30 can be positionedexternally on the skin of the patient 50. As used herein, “single-use”is used to refer to a use for a single patient during a treatmentsession. The sensor patch 30 is typically worn once proximate in timeand during a treatment. In other embodiments, the sensor patch 30 may beepisodically worn or continuously worn over a target period. It will beunderstood that a treatment session may include an active radiotherapyadministration during a single treatment session or serially spacedapart treatment sessions. The treatment session may have a duration ofminutes, hours, days and the like. Furthermore, a calibration doseobtained before the sensor patch 30 is positioned on a patient is not tobe considered the “single-use.”

[0086] As shown in FIG. 1, a plurality of sensor patches 30 are locatedboth on the front and back of the patient 50. The sensor patches 30 areconfigured to change an operational parameter in a predictable mannerthat correlates to radiation dose it receives, as will be discussedfurther below. The sensor patch 30 can be configured so as to beself-contained and discrete and devoid of dangling lead wires extendingto a remote power source or operating system during use and in positionon the patient. As such, a reader, for example, reader 75 (FIGS. 6 and7), can be configured to obtain the data from the sensor patch 30 by,for example, electrically contacting with each sensor patch 30 ofinterest.

[0087] As used herein, the reference number “75” will be used to refergenerally to a reader device according to embodiments of the presentinvention. Particular embodiments of a reader device 75 may be referredto using the reference number 75 and one or more primes attachedthereto. For example, particular embodiments of the reader device may bedenoted 75′ or 75″. This convention may similarly be used with respectto other features of the present invention. For example, the referencenumber “30′” will be used to refer to particular embodiments of a sensorpatch herein. It will be understood that features discussed with respectto any embodiment of the present invention may be incorporated intoother embodiments of the present invention even if these features arenot discussed specifically with reference to each individual embodiment.

[0088] Referring to FIG. 2, operations that can be carried out tomonitor the radiation dose that is delivered to a patient undergoingradiation therapy are illustrated. At least one single-use dosimetersensor patch can be releasably secured to the skin of the patient (block100). In certain embodiments, the sensor patch may be calibrated and/orpre-dosed before being attached to the patient (block 101). Thecalibration and/or pre-dosing of the sensor patch may be done on anindividual patch basis or many sensor patches may be calibrated and/orpre-dosed in batches simultaneously as discussed further below. Incertain embodiments, the patch(es) can be conveniently attached to thepatient in operation-ready condition before the patient enters theradiation treatment room or chamber (block 102) to limit or reduce theset-up time required or the “down-time” of the equipment or thetreatment room. In other words, the sensor patch or patches may besecured to the patient prior to his/her entry into the radiationtreatment room. A pre-irradiation or pre-dose measurement or reading ofdata associated with an operational parameter of the sensor patch(es) 30can be obtained prior to initiation of the radiation treatment (block105). The data can be obtained in situ, with the sensor patch(es) 30 inposition on the patient. Alternatively, the pre-dose data can beestablished prior to positioning the sensor patch(es) onto the subjectas discussed above and the data then transferred to the reader orassociated controller and/or computer at a desired time.

[0089] In certain embodiments of the sensor patch(es), thepost-radiation reading can be taken when the patient leaves thetreatment room to evaluate the dose delivered during the treatmentsession to limit the amount of room-use time. The sensor patches 30 canbe removed from the patient and then read by a handheld portable and/ora bench top reader. In other embodiments, the reading can be obtainedwhile the sensor patches 30 remain on the patient. In certain particularembodiments, the reading may be able to be obtained in situ during thetreatment session (without removing the sensor patch(es) from thepatient) to provide real-time feedback to the clinician estimatingwhether the desired dose is being administered to the patient. Incertain embodiments, the temperature of the sensor patch (such as at alocation adjacent the circuitry) or of the subject (skin or core body)can also be ascertained or obtained and taken into account whencalculating the radiation dose. In any event the dose reading can beobtained without requiring external powering or externally appliedbiasing of the sensor patches 30 during the radiation treatment.

[0090] In certain embodiments, a plurality of discrete sensor patches 30can be positioned to cover a region on the skin that is in the radiationbeam path so as to reside over the tumor site. In particularembodiments, one or more sensor patches 30 can also be positioned inradiation sensitive areas of the body to confirm stray radiation is notunduly transmitted thereto. FIG. 1 illustrates that a sensor patch canbe located at the neck over the thyroid when the tumor site is over thechest region. As such, sensitive regions include, but are not limitedto, the thyroid, the spine, the heart, the lungs, the brain, and thelike.

[0091] In any event, referring again to FIG. 2, radiation isadministered to the patient in a first treatment session (block 110).Data associated with a change in an operational parameter in thedosimeter sensor patch circuitry may be obtained from the sensor patchusing a reader device (block 120) after administering the radiation tothe patient (block 110). In certain embodiments, a sensor patch may beremoved from the patient and inserted into the reader device to transferthe data from the sensor patch. In further embodiments, the readerdevice may contact the sensor patch as discussed further below. In stillfurther embodiments, the reader may transfer data, from the sensor patchwirelessly. The radiation dose received by the patient can be determinedbased on the obtained data (block 125).

[0092] In some embodiments of the present invention, the obtained datamay include a voltage threshold of a metal-oxide semiconductorfield-effect transistor (MOSFET) included on the at least one sensorpatch 30. In these embodiments of the present invention, a pre-radiationvoltage threshold of the MOSFET and a zero temperature coefficient ofthe MOSFET may be measured before the patient undergoes radiationtherapy (block 108). The pre-radiation threshold voltage and the zerotemperature coefficient of the MOSFET may be stored in the electronicmemory of the at least one sensor patch (blocks 109 and 130). The storedzero temperature coefficient may be used to bias the MOSFET (block 124)on the at least one sensor patch 30 after the patient undergoesradiation therapy and before the post-radiation threshold voltage ismeasured as discussed further below.

[0093] It will be understood that the radiation dose may beautomatically determined by the reader 75 without any input by a doctoror technician. However, in some embodiments of the present invention,the doctor or technician may be prompted for additional information(block 123) by the reader 75 to determine the radiation dose. Forexample, the reader 75 may prompt the technician for a correction factorrelated to the sensor patch 30 and/or, radiation type, equipment set-upand the like. The prompts may be carried out before and/or after theirradiation. Once the doctor or technician supplies the requestedadditional information, the reader 75 may automatically determine theradiation dose using the additional information provided. The obtaineddata, as well as other information, may be stored in an electronicmemory (memory device) included on the sensor patch (block 130).

[0094] In particular, the electronic memory may include methodology datathat instructs the reader 75 how to interface with, i.e., obtain datafrom, the sensor patch(es) 30. In particular, the electronic memory mayinclude methodology data that instructs the reader 75 how to interfacewith, i.e., obtain data from, the sensor patch(es) 30. Thus, forexample, if the patch 30 changes electronic configuration, the patch 30can be configured to automatically instruct the reader 75 on how toobtain the radiation and other patch data of interest, allowing thereader 75 to operate with different versions of patches. In otherembodiments, the reader 75 can be periodically upgraded with software tocommunicate with the different versions of patches. Combinations ofthese configurations may also be used.

[0095] The electronic memory may further include radiation-dose data,patient data, time and date of a radiation reading, calibration data andthe like. Furthermore, as discussed above, the electronic memory mayinclude the zero temperature coefficient of a MOSFET included on thesensor patch 30. This zero temperature coefficient may be used to biasthe MOSFET after the radiation treatment before a post-radiationthreshold voltage is obtained as discussed further below.

[0096] The sensor patch 30 does not require lead wires extending from aremote power source or computer system to operate (i.e., is basicallyinactive and/or unpowered) during irradiation. For example, where aMOSFET-based radiation sensor circuit is used, the MOSFET is generallypassive but collects a permanent space charge as a result of the passageof ionizing radiation. After radiation exposure or at a desiredevaluation time, the biosensor(s) can be inductively powered and theMOSFET-based radiation data can be wirelessly transferred to a remotereader.

[0097] Instead, the sensor patch 30 is configured to be a discretepatch(es) (or a patch array of sensors). In some embodiments, the patch30 can transmit or relay radiation data upon contact with and/orinsertion into a reader device 75 and may store data in an electronicmemory device included on the sensor patch. As discussed above, incertain embodiments, the sensor patch 30 may be configured tocommunicate wirelessly with the reader 75. The radiation dose receivedby the sensor patch 30 can be determined and used to estimate the dosereceived by the patient during the radiation therapy session based onthe data obtained by the reader. The reader 75 itself can be a handheldportable unit that may or may not require wires to connect with a remotecontroller or computer or may use a standard communication port as willbe discussed further below. The reader 75 can include a user input suchas a touch screen and/or keypad entry. In any event, the operations canbe carried out for each or a selected radiation treatment session. Ifthe operations are repeated for each treatment session, a cumulativeamount of delivered radiation can be estimated/confirmed to allow aclinician to evaluate whether additional treatments are desired.

[0098]FIG. 3A illustrates that the sensor patches 30 can be provided ina kit or set 130 including a plurality of sensors 30 p. The plurality ofsensors 30 p may be configured in sufficient numbers or types for asingle patient or so as to be able to supply sensors across a pluralityof patients. In certain embodiments, a strip of six sensor patches 30can be packaged together as a set 130′ as shown in FIG. 15A. It iscontemplated that, depending on the treatment type, the treatmentlocation, the tumor site, and the like, different numbers of sensorpatches 30 may be used for different patients. Thus, if the sensor kit130 is sized for a single patient, the kit may include from about 2 toabout 10 or more sensor patches 30 that can be selectively chosen foruse by the clinician. Each sensor patch 30 can be sterilized and sealedin a sterile package or the kit 130 itself can be sized and configuredto hold a plurality of the sensor patches 30 p in a sterile packagethat, once opened, can be either used or discarded. Similarly, if thesensor kit 130 is sized for multi-patient use, then larger quantitiesmay be packaged individually, or in sets within the multi-patientpackage, together. The sterilization can be performed by heat orchemical exposure, such as by ethylene oxide sterilization. In certainembodiments, sterilization and/or sterile packaging may not be required.

[0099] As is also shown in FIG. 3A, each sensor patch 30 can be packagedwith pre-irradiation characterizing data 132. This data 132 can beincluded in optically or electronically readable formats such as in barcode format for the reader to be able to read without having theclinician enter the information into a controller/computer. In certainembodiments, the data 132 may be included in a memory storage device 67,for example, an electrically programmable memory such as an electricallyerasable read only programmable memory (EEPROM), provided on each sensorpatch 30 p as discussed further below. The memory storage device 67 mayinclude information such as patient identification, time, date,hospital, therapist, state of the device, dosed/undosed sensor data andcalibration data. The memory storage device 67 may further be used tostore bias parameters and/or information with respect to measurementmethodology for each individual patch 30. For example, the measurementmethodology may include instructions for the reader 75 on how tocommunicate with the sensor patch 30. Including these instructions inthe memory storage device may allow the reader 75 to operate with anyversion of the sensor patch 30 as the reader 75 may not have to beconfigured for the specifications of a particular sensor patch 30. Insome embodiments of the present invention, the memory storage device 67of the sensor patch 30 may have at least 2K of storage thereon.

[0100] Each sensor patch 30 can have an individual calibrationcoefficient, dose data or characterizing data label located on thesensor patch 30 or as a corresponding label held with the package or kit130. In other embodiments, each sensor patch 30 produced in a commonproduction run (off of the same wafer or chip) with substantiallysimilar characterizing data may be packaged together and a singlecalibration characterizing data or label 132 can be included with theset 130 or sets or production run. In certain embodiments, thecalibration related characterizing data can include the pre-irradiationthreshold voltage value of a MOSFET(s) that is measured at an OEM andprovided in or with the sensor patch set 130.

[0101] In further embodiments, the memory storage device 67 may includea zero temperature bias parameters associated with the MOSFET includedon the sensor patch 30. The zero temperature coefficient of the MOSFETmay be measured prior to administration of radiation therapy to thepatient and stored in the memory storage device 67. The zero temperaturecoefficient of the MOSFET may be used to bias the MOSFET beforeobtaining a post-radiation threshold voltage value of the MOSFET asdiscussed further below.

[0102] Referring now to FIG. 19, Table 1 summarizes exemplaryspecifications for the sensor patch 30 according to some embodiments ofthe present invention. It will be understood that the specificationsprovided in Table I are provided for exemplary purposes only and thatembodiments of the present invention should not be limited to thisconfiguration.

[0103] In certain embodiments, identifying indicia may be disposed onthe sensor patches 30 to allow a clinician to easily visually identifyand/or account for the sensors used. For example, FIG. 3A illustratesthree discrete sensor patches labeled as 1F, 2F, and 3F as well as asensor with a pictorial representation of a heart 4F (other visualimages can also be used such as a yellow caution sign, other anatomicalsymbols, and the like). In some embodiments of the present invention,the patches may be configured to accept direct indicia using, forexample, a marker or a pen thereon. The heart or caution sensor patch 30s can be positioned in a radiation sensitive area to detect the amountof radiation delivered to that area. Typically, the radiation beam isadjusted to reduce the radiation exposure to sensitive areas and acaution-sensitive sensor patch 30 s (or patches) can indicate whetheradjustments need to be made to reduce the detected exposure for each orselected treatment sessions. The sensor patches 30 s used for sensitivedetection may be configured with increased sensitivity for enhanced doseresolution capability for measuring small, residual, or stray doses ofradiation (such as those located over critical organs which are not inthe treatment volume). For example, for “normal” single use sensors maybe configured to operate over a range of between about 20-500 cGy; the“high sensitivity” sensor might be configured to operate from about 1-50cGy. In particular embodiments, the circuit 30 c (FIG. 9A) for the highsensitivity sensor 30 s includes at least one radiation-sensitivefield-effect transistor (RADFET) that can be configured to produce alarger threshold voltage shift for a given amount of received orabsorbed dose relative to the sensors 30 positioned in the window of thetargeted treatment volume. The larger voltage shift may increase doseresolution and possibly dose repeatability.

[0104] In addition, single-use dosimeters can be optimized to work overa much lower dose range than multiple use dosimeters. Since the typicalper day fraction for radiation therapy is about 200 cGy, the dosimetersensor 30 can be optimized for accuracy and repeatability over this doserange. A 20-500 cGy operating range should meet performance goals whileproviding adequate flexibility for varying treatment plans. Amultiple-session fraction dosimeter sensor 30 may require a much largerdose range that depends on the number of fractions over which the sensorwill operate. As used herein, “disposable” means that the sensor patchis not reusable and can be disposed of or placed in the patient'srecords.

[0105] As shown in FIG. 3A, the indicia can include an alphanumericidentifier such as the letter “F” located to be externally visible onthe sensor patches 30. The letter “F” can represent that the sensors areplaced on a first side or front of the patient. FIG. 3B illustrates thata second set of sensors 130′ can be supplied, these sensor patches 30can be labeled with different indicia, such as 1B, 2B, 3B and the like,representing that they are located at a different location relative tothe first set (such as a second side or back of the patient). Using datafrom opposing outer surfaces can allow an interpolated radiation doseamount to be established for the internal tumor site.

[0106] It will be understood that the indicia described above, namely“F” and “B”, are provided herein for exemplary purposes only and thatindicia according to embodiments of the present invention are notlimited by the examples provided. Any label, mark, color or the like maybe used that would serve to distinguish one patch or set of patches fromanother patch or set of patches without departing from the teachings ofthe present invention. For example, instead of “F” and “B”, the firstset of patches 130 may be blue and the second set of patches 130′ may bered. Furthermore, the indicia may be, for example, on the sensor patchitself or on an adhesive covering placed on or over the sensor patchwithout departing from the teachings of the present invention.

[0107]FIG. 3C illustrates a patient anatomical map 150 that can be usedto identify where each of the sensor patches 30 are placed on the bodyof the patient. The map 150 may be stored in the patient chart or file.For each treatment session for which dose monitoring is desired, theclinician can allocate the same sensor patch identifier (“A”, “1F”, etc. . .) to the same location. The map 150 and/or indicia on the sensorpatches 30 can, in turn, help the clinician consistently identifywhether a particular location may have undue or deficient exposure. Forexample, if sensor patch F1 indicates a low radiation exposure, while F3indicates a relatively high exposure, and the two are positioned in thetargeted beam region, either one or both of the sensor patches 30 is notfunctioning properly, or the radiation beam may need adjustment. Usingsubstantially the same sensor patch position for successive treatmentsessions may allow cumulative radiation dose data to be obtained andcorrelated to provide a more reliable indication of dose. The clinicianmay also draw markings on the patient's skin to help align the sensorpatches 30 in relation thereto over the different treatments sessions.

[0108] In certain embodiments, the discrete sensor patches 30 can bearranged to reside on a common substrate or to be attached to each otherso as to define known or constant distances therebetween (not shown).The sensor patches 30 may be configured to be at the body temperature ofthe patient during use or at room temperature, or temperatures inbetween. In certain embodiments, to establish a calculated dose amount,a temperature reading may be obtained, assumed, or estimated. In certainparticular embodiments, the temperature may impact the operationalchange if substantially different from that upon which the calibrationdata is established. In some embodiments, the at least one sensor patch30 can be used with other therapies that generate radiation andpotentially expose a patient to radiation. For example, but not limitedthereto, at least one sensor patch 30 can be mounted to a patient duringa fluoroscopic procedure to evaluate the skin radiation exposure.

[0109] In certain embodiments, a first set-up pre-dose verificationprotocol can be carried out to deliver a first radiation dose and afirst radiation dose value can be obtained for at least one selectedpatch to confirm that the radiation beam focus location is correct orsuitable (or whether a sensitive area is receiving radiation). Inaddition, the system can be configured to map a dose gradient bycorrelating the determined radiation dose values at each patch locationto the anatomical location on the subject of each patch.

[0110]FIG. 4 illustrates an exemplary patient dosimetry form 99, whichmay be, for example, a paper sheet or computer printable document. Theform 99 can contain an anatomical map 150 as discussed above withrespect to FIG. 3C. Sicel Technologies, Inc. asserts copyrightprotection for the form illustrated in FIG. 4 and has no objection toreproduction of the patent document, as it appears in the Patent andTrademark Office patent file or records, but reserves all other rightswhatsoever.

[0111] As discussed above, the map 150 may be used to identify and/ormemorialize for the patient record where each of the sensor patches 30are placed on the body of the patient during use. An anatomical map 150can be used to record the specifics of each radiation session and may beplaced in each patient's chart or file to assist the doctor and/orclinician. Patients being treated on an ongoing basis may have multipledosimetry forms 99 in their chart and/or file corresponding to eachtreatment session. As noted above, for each treatment session, theclinician can, as desired, allocate the same sensor patch identifier tothe same location aided by the map 150. As further illustrated in FIG.4, the dosimetry form 99 may further include a dosimetry plan portion152, a measurement data portion 154 and a sensor patch record portion156.

[0112] The dosimetry plan portion 152 may include the patient's name,the date or dates the patient is scheduled for the treatment, thepatient's doctor, and any information that may be specific to thepatient or the patient's treatment. The measurement data portion 154 mayinclude information such as the date of the treatment and the therapistadministering the treatment on that date. The sensor patch recordportion 156 may include labeled sections 158 (A, B, . . . ) giving eachpatient a discrete identifier which may correspond to sensor patchlocations (A, B, . . . ) with the identifiers indicated on theanatomical map 150. The sensor patch record portion 156 may furtherinclude dosing data, for example, target and measured doses asillustrated in FIG. 4. The sensor patch record portion 156 may furtherinclude the actual sensor patch used on the patient in each of thelabeled sections 158. As shown, the form 99 can include two separatestorage regions, namely a pre and post dose use storage region. Inaddition, the form 99 can also allow a clinician to indicate whether thesensor patch was held in the entrance and/or exit field.

[0113] In certain embodiments, the sensor patch 30 may contain a storageor memory device 67 (FIGS. 3A, 9B), the storage or memory device on thesensor patches may be accessed to determine dosing information etc. ifthis information fails to be recorded, is misplaced or requiresverification. Furthermore, the memory device 67 included on the sensorpatch 30 may further include the data recorded in the map portion 150,the dosimetry plan portion 152 and the measurement data portion 154 ofthe dosimetry form 99. Accordingly, the memory device 67 on the sensorpatch 30 may serve as an electronic dosimetry patient record form. Itwill be understood that the dosimetry form 99 of FIG. 4 is provided forexemplary purposes only and that the present invention may provide dataand/or hold sensor patches in alternate manners without departing fromthe teachings of the present invention.

[0114]FIG. 5A illustrates the use of five primary sensor patches 30positioned over the targeted treatment region (on the front side of thepatient) and one sensor patch 30 s positioned over the heart. FIG. 5Billustrates three primary sensors 30 located over the back surfaceproximate the area corresponding to the underlying tumor site 25.

[0115]FIG. 6 illustrates a reader or data acquisition device 75′according to embodiments of the present invention, in point contact withthe underlying sensor patch 30 in order to detect the amount ofradiation that the sensor patch 30 was exposed to during (or after) thetreatment session. In certain embodiments, as discussed above, thesensor patch(es) 30 can be secured to a patient's chart or dosimetryform 150 and read after removal from the patient. The reader 75′illustrated in FIG. 6 may be configured to contact a portion of anelectrical circuit on the sensor patch 30 that includes a device thathas an operating characteristic or parameter that changes upon exposureto radiation in a predictable manner to allow radiation doses to bedetermined. The reader 75′ can be configured with a probe 75 p that isconfigured to electrically contact an electrically conductive proberegion on the sensor patch 30 so as to obtain a reading in a “short”time of under about 30 seconds, and typically in less than about 5-10seconds, for each of the sensor patches 30.

[0116] Referring now to FIG. 7A a sensor patch 30′ disposed in a readeror data acquisition device 75″ according to further embodiments of thepresent invention. Sensor patches 30′ according to embodiments of thepresent invention may be adapted to be inserted into the reader 75″.Similarly, the reader 75″ is adapted to receive the sensor patch 30′. Asshown, the sensor patch 30′ is formed to include a tab portion 36 thatat least a portion of is sufficiently rigid to sustain its shape forproper electrical coupling when inserted into a port 32 in the readerdevice 75″. As further illustrated in FIG. 7A, the reader 75″ mayinclude a sensor port 32 and the sensor patch 30′ may be inserted intothe port 32 in the reader 75″ in order to detect the amount of radiationthat the sensor patch 30′ was exposed to. The port 32 can read thesensor patch 30 as it is held in selected orientations in the port 32.The port 32 may be configured similar to conventional devices that read,for example, glucose strip sensors and the like. The port 32 illustratedin FIG. 7A may contain one or more electrical contacts configured tocontact one or more electrical contacts on the sensor patch 30′ toelectrically connect the reader 75″ to an electrical circuit on thesensor patch 30′. The electrical circuit on the sensor patch 30′includes a radiation-sensitive component that has an operatingcharacteristic or parameter that changes upon exposure to radiation in apredictable manner to allow radiation doses to be determined. As before,the reader 75″ may obtain a reading in under about 30 seconds, andtypically in less than about 5-10 seconds, for each of the sensorpatches 30.

[0117] The reader device 75″ can be held in a portable housing 37. Itmay be pocket sized and battery powered. In certain embodiments, thereader device 75 may be rechargeable. As shown in FIGS. 7, 15A and 15B,the reader 75 may include a display portion 75 d, for example, a liquidcrystal display (LCD), to provide an interface to depict data to thedoctor and/or technician.

[0118] The function of the reader device 75 may be incorporated into anyportable device adapted to receive a sensor patch 30 in, for example, asensor port 32. For example, the reader 75 functionality/circuitry couldbe disposed in a personal digital assistant (PDA) that is adapted toinclude a radiation sensor port 32. The reader 75 may further include aremote computer port 33. The port 33 may be, for example, RS 232,infrared data association (IrDA) or universal serial bus (USB), and maybe used to download radiation and/or other selected data from the sensorpatch 30 to a computer application or remote computer.

[0119] As illustrated in FIG. 7B, in some embodiments, the sensor patch30 and the reader device 75′″ may both be equipped with a radiofrequency (RF) interface and information may be shared between thereader device 75′″ and the sensor patch 30 using wireless signals 38without departing from the scope of the present invention. Exemplaryembodiments of a reader 75 according to embodiments of the presentinvention are provided in commonly assigned U.S. Design patentapplication Ser. No. 29/197934 entitled Portable Oncologic ExternalDosimeter Reader, filed Jan. 21, 2004, the content of which are herebyincorporated herein by reference as if set forth in its entirety.

[0120] In certain embodiments, as noted above, the sensor patch 30includes a storage or memory device 67. In these embodiments, the reader75 may be configured to obtain data stored in the memory device 67 ofthe sensor patch 30 using, for example, electrical contacts on thereader 75 and the patch 30, to transfer the data stored in the memorydevice 67 of the sensor patch 30. This data obtained from the sensorpatch memory device 67 may, for example, be stored locally on the reader75 or be downloaded to an application on, for example, a remote computerusing a port 33 provided in the reader 75. The memory device 67 on thesensor patch 30 may serve as a permanent record of the radiation doseand may contain a real time clock such that the obtained data mayinclude a time and date stamp.

[0121] An exemplary block diagram of a reader 75 and a sensor patch 30including a RADFET 63 and an electronic memory 67 according to someembodiments of the present invention is provided in FIG. 20. It will beunderstood that the block diagram of the reader 75 and the sensor patch30 of FIG. 75 is provided for exemplary purposes only and embodiments ofthe present invention should not be limited to the configurationprovided therein. Furthermore, a flow diagram 2100 of FIG. 21illustrates how a number of reads, a read delay and/or a rate may modifyconversion parameters of the RADFET according to some embodiments of thepresent invention.

[0122]FIG. 8A illustrates exemplary embodiments of a sensor patch 30. Asshown, the sensor patch 30 includes a substrate layer 60, a circuitlayer 61, and an upper layer 62 that may be defined by a coating, film,or coverlay material. The substrate layer 60 can be selected such thatit is resilient, compliant, or substantially conformable to the skin ofthe patient. Examples of suitable substrate layer materials include, butare not limited to, Kapton, neoprene, polymers, co-polymers, blends andderivatives thereof, and the like. The underside or bottom of the sensorpatch 30 b may include a releasable adhesive 30 a so as to be able toattach to the skin of the patient. The adhesive 30 a can be a medicalgrade releasable adhesive to allow the sensor patch 30 to be secured tothe skin during the treatment session and then easily removed withoutharming the skin. The adhesive 30 a can be applied to portions, or all,of the bottom surface of the substrate layer 60. A releasable liner canbe used to cover the adhesive, at least prior to positioning on thepatient. In certain embodiments, the underside of the sensor patch 30 bmay be free of the adhesive. In these embodiments, an adhesive coverlay30 cl (FIG. 9C) may be placed over the body of the sensor patch 30 tosecure the sensor patch 30 to the patient. The adhesive coverlay 30 clmay be sized to extend beyond the outer perimeter of the sensorsubstrate 60. The adhesive may be on a portion or all of the undersideof the coverlay 30 cl.

[0123] In other embodiments, the sensor patch(es) 30 is configured as adiscrete, low profile, compact non-invasive and minimally obtrusivedevice that conforms to the skin of the patient. The sensor patch(es)may be less from about 0.25 to about 1.5 inches long and wide and have athin thickness of from about 1 to about 5 mm or less. As such, thesensor patches 30 can, in certain particular embodiments, be secured tothe patient and allowed to reside thereon for a plurality or all of thesuccessive treatments. For example, the sensor patches 30 can beconfigured to reside on the patient in its desired position for a 1-4week, and typically about a 1-2 week period. In this manner, the samesensor patches 30 can be used to track cumulative doses (as well as thedose at each treatment session). An adhesive may be applied in aquantity and type so as to be sufficiently strong to withstand normallife functions (showers, etc.) during this time. Of course, selectedones of the sensor patches 30 can also be replaced as desired over thecourse of treatment as needed or desired.

[0124] In certain embodiments of the present invention, the sensor patch30 can be attached to the patient so that it makes and retains snugcontact with the patient's skin. Air gaps between the sensor 30 and thepatient's skin may cause complications with respect to obtaining theestimated dosage data. As illustrated in FIGS. 9D and 9E, someembodiments of the present invention include the placement of an overlaymaterial 30 fl over the sensor patch 30 to, for example, simulateplacement of the sensor patch 30 beneath the patient's skin. This typeof simulation may inhibit scatter of the radiation beam and/or establishelectronic equilibrium in proximity to the sensor patch 30 and,therefore, increase the reliability of radiation measurement. Radiationmeasurement using the sensor subsurface electronics may be optimal atfrom about 0.5 to about 3 cm beneath the patient's skin, but typicallyis from about 1 to about 1.5 cm beneath the patient's skin. Accordingly,the overlay material 30 fl may be from about 0.5 to about 3 cm thick tosimulate subsurface depth measurement conditions. The presence of thisoverlay material 30 fl may decrease the influence of air gaps betweenthe sensor 30 and the patient's skin.

[0125] The overlay material 30 fl may be, for example, a resilientflubber like or flexible material that will conform to the skin such asan elastomeric or the like. As illustrated in FIG. 9D, the overlaymaterial 30 fl may be placed between the adhesive coverlay 30 cl and thesensor patch 30 such that the adhesive coverlay 30 cl adheres the sensorpatch 30 and the overlay material 30 fl to the patient's skin. Asillustrated in FIG. 9E, the overlay material 30 fl may be placed overthe adhesive coverlay 30 cl and the sensor patch 30. In certainembodiments, the overlay material may have adhesive properties such thatthe overlay 30 fl may be adhered to the patient's skin. The overlaymaterial 30 fl may also be integrated with the sensor patch 30 withoutdeparting from the teachings of the present invention.

[0126] As further illustrated in FIGS. 18A and 18B, some embodiments ofthe present invention include the placement of a buildup cap 180 overthe sensor patch 30 to, for example, simulate placement of the sensorpatch 30 beneath the patient's skin. This type of simulation may help tofocus a narrow portion of the radiation beam in proximity to the sensorpatch 30 and, therefore, increase the reliability of radiationmeasurement. As further illustrated in FIG. 18A, the buildup cap 180 mayhave a hemispherical shape and may simulate placement of the sensorpatch 30 inside the body to a depth called “Dmax”. Dmax may be, forexample, from about 1 to about 3 cm and is the depth at which theabsorbed dose reaches a maximum for a given energy. The buildup cap 180may include a material equivalent to water and a metallic material. Forexample, the buildup cap 180 may include a layer of polystyrene 182having a diameter of from about 6 to about 7 mm and a layer of copper181 on the polystyrene have a thickness of about 0.5 to about 1 mm.

[0127] The buildup cap 180 may include a small lip (not shown) thathooks onto the front edge of the patch for consistent alignment. Thebuildup cap 180 may have a medical grade adhesive that would stick well,but not permanently, to the top face of the sensor patch 30. In someembodiments of the present invention, the geometry of the cap could bemade to help with isotropy. The buildup cap 180 may be placed on thesensor patch 30 separately based on the energy range of the buildup cap180, thereby allowing the underlying sensor patch 30 to be used withdifferent buildup caps 180 for different energy ranges. In someembodiments of the present invention, the buildup caps 180 may beprovided in different colors, the colors indicating the energy range ofthe buildup cap 180. Thus, in some embodiments of the present invention,the bulk of the buildup cap 180 may be injection molded polystyrene 182that is coated with a copper layer 181 and some rubbery or elastomericsurface paint applied in different colors corresponding to the differentenergy ranges provided by the buildup cap 180. The buildup cap 180 canalso be shaped to provide a measurement that is independent of X-raybeam entry angle.

[0128] It will be understood that the buildup cap 180 may be placedbetween the adhesive coverlay 30 cl and the sensor patch 30 such thatthe adhesive coverlay 30 cl adheres the sensor patch 30 and the buildupcap 180 to the patient's skin. It will be further understood that thebuildup cap 180 may also be placed over the adhesive coverlay 30 cl andthe sensor patch 30 without departing from the scope of the presentinvention

[0129] Still referring to FIG. 8A, the sensor circuit layer 61 can beattached to, and/or formed on, the underlying substrate layer 60. Theupper layer 62 can be configured as a moisture inhibitor or barrierlayer that can be applied over all, or selected portions of, theunderlying circuit layer 61. It is noted that, as shown, the thicknessof the layers 60-62 are exaggerated for clarity and shown as the samerelative thickness, however the thickness of the layers may vary. Incertain embodiments, the sensor patch 30 is configured as a low profile,thin device that, when viewed from the side, is substantially planar.

[0130]FIG. 8B is a top view of embodiments of a sensor patch 30. Asshown, in certain embodiments, the circuit layer may include twoconductive probe contacting regions 30p. During datareadings/acquisitions, the probe contacting regions 30 p are configuredto provide the connections between the operating circuitry on thecircuit layer 61 and the external reader. The probe contacting region(s)30 p can be directly accessible or covered with a protective upper layer62. If directly accessible, during operation, the reader 75 can merelypress against, contact or clip to the sensor patch 30 to contact theexposed surface of the conductive probe region 30 p to obtain thereading. If covered by an upper layer 62 that is a protective coating orother non-conductive insulator material, the clinician may need to forman opening into the coating or upper layer over the region 30 p so as tobe able to penetrate into the sensor patch 30′ a certain depth to makeelectrical contact between the probe region 30 p and the probe of thereader 75 p.

[0131]FIG. 8C illustrates a probe portion 75 p of the reader 75′ of FIG.6. As illustrated, the probe portion 75 p may be configured so that theprobe 75 p includes, for example, conductive calipers, pinchers, orother piercing means, that can penetrate to make electrical contact withthe probe contacting region 30 p of the sensor patch.

[0132]FIG. 9A illustrates a top view of embodiments of a circuit layer61. As shown, the circuit layer 61 includes the radiation sensitiveoperative sensor patch circuitry 30 c that is self-contained and devoidof outwardly extending or hanging lead wires that connects to anoperational member. The sensor patch circuitry 30 c includes a radiationsensitive device 63 that exhibits a detectable operational change whenexposed to radiation. In certain embodiments, the radiation sensitivedevice 63 is a miniaturized semiconductor component such as a MOSFET.Suitable MOSFETs include RADFETs available from NMRC of Cork, Ireland.In certain embodiments, the MOSFET may be sized and configured to beabout 0.5-2 mm in width and length. The circuitry 30 c also includes atleast one conductive lead or trace 64 extending from the radiationsensitive device 63 to the conductive probe contacting region 30 p. Inthe embodiment shown, the conductive probe contacting region 30 p is anannular ring. As also shown there are two traces 64 i, 64 o that connectthe device 63 to the ring 30 p. The traces or leads 64′ may be formed,placed, or deposited onto the substrate layer 60 in any suitable mannerincluding, but not limited to, applying conductive ink or paint or metalspray deposition on the surface thereof in a suitable metallic pattern,or using wires. As desired, an upper layer 62 such as described above(such as epoxy) may be formed over the circuit layer 61 (or even theentire sensor patch). The sensor patch 30 may include integrated ElectroStatic Discharge (ESD) protection, the reader 75 may include ESDprotection components, or the user/operator may use ESD straps and thelike during readings.

[0133] In particular embodiments, the sensor patch 30 and circuit 30 ccan be configured with two or more MOSFETS. In embodiments configured tohave two MOSFETS, one may be positioned over the other on opposing sidesof the substrate in face-to-face alignment to inhibit orientationinfluence of the substrate. (not shown). Additionally, other materials,e.g., certain epoxies, can be used to both encapsulate the MOSFETs andprovide further scattering influence to facilitate isotropic response ofthe MOSFETs. In addition, there are well known influences of radiationbackscatter from the surface of patients on whom surface-mounteddosimeters are used. The backscatter effect can be taken into accountwhen calculating an entrance or exit dose or sufficient build-up may beprovided on the top of the dosimeter to promote the equilibration ofscattered electrons. See, Cancer, Principles and Practice of Oncology,3d edition, ed. V T DeVita, S. Hellman, and S A Rosenberg (J BLippincott Co., Phila., 1989), the contents of which are herebyincorporated by reference as if recited in full herein.

[0134]FIG. 9B is a top view of further embodiments of a sensor patch 30′that includes a tab portion 36 that is adapted to be received by areader, for example, reader 75″ illustrated in FIG. 7. As shown, thecircuit 30 c′ includes a circuit layer 61 that includes at least oneelectrical contact 31 shown as a plurality of substantially parallelleads. During data readings/acquisitions, the sensor patch 30′ isinserted into the reader port 32 of the reader 75″ (FIG. 7) and the atleast one electrical contact 31 is configured to provide the electricalconnections between the operating circuitry on the circuit layer 61 andthe external reader 75″. The electrical contact(s) 31 may be coveredwith a protective upper layer 62 (FIG. 8A). If covered by an upper layer62 that is a protective coating or other non-conductive insulatormaterial, the clinician may need to form an opening into the coating orupper layer over the electrical contact(s) 31 so these contact(s) 31 maymake electrical contact with the reader via sensor port 32 (FIG. 7).

[0135]FIG. 9B further illustrates the circuit layer 61 that includes theradiation sensitive operative sensor patch circuitry 30 c′. The sensorpatch circuitry 30 c′ includes a radiation sensitive device 63 thatexhibits a detectable operational change when exposed to radiation andmay include a memory device 67. In certain embodiments, the radiationsensitive device 63 is a miniaturized semiconductor component such as aMOSFET. Suitable MOSFETs include RADFETs available from NMRC of Cork,Ireland. In certain embodiments, the MOSFET may be sized and configuredto be about 0.5-2 mm in width and length. The circuitry 30 c′ alsoincludes at least one conductive lead or trace 64′ extending from theradiation sensitive device 63 and/or the memory device 67 to the atleast one electrical contact(s) 31. The traces or leads 64′ may beformed, placed, or deposited onto the substrate layer 60 in any suitablemanner including, but not limited to, applying conductive ink or paintor metal spray deposition on the surface thereof in a suitable metallicpattern, or using wires. As desired, an upper layer 62 such as describedabove (such as epoxy) may be formed over the circuit layer 61 (or eventhe entire sensor patch). Each sensor patch 30 may be from about 0.25 toabout 1.5 inches long and wide and have a thin thickness of from about 1to about 5 mm or less.

[0136] As discussed above with respect to FIG. 8A, the underside orbottom of the sensor patch 30 b may include a releasable adhesive 30 aso as to be able to attach to the skin of the patient. The adhesive 30 acan be a medical grade releasable adhesive to allow the sensor patch 30to be secured to the skin during the treatment session and then easilyremoved without harming the skin. The adhesive 30 a can be applied toportions, or all, of the bottom surface of the substrate layer 60.Referring now to FIG. 9C, in certain embodiments, the underside of thesensor patch 30 b may be free of the adhesive. As illustrated, anadhesive coverlay 30 cl may be placed over the entire body of the sensorpatch 30 to secure the sensor patch 30 to the patient. As furtherillustrated, the adhesive coverlay 30 cl may be sized to extend beyondthe outer perimeter of the sensor substrate 60 and leave the tab portion36 of the sensor 30′ exposed. The adhesive provided on the underside ofthe coverlay 30 cl may be provided on a portion of the coverlay 30 cl,for example, the portion of the coverlay 30 cl contacting the patient'sskin outside the perimeter of the sensor substrate 60, or on the entireunderside of the coverlay 30 cl.

[0137] Sensor patches 30 according to embodiments of the presentinvention may be provided individually or in sheets containing multiplesensor patches 30. In particular, the sensor patches 30 may befabricated in high-density sheets. As used herein, “high density” refersto multiple sensor patches provided on a unitary sheet. High density isintended to encompass very large sheets containing, for example,hundreds or thousands of sensors, as well as, for example, 3×3 regionsof these very large sheets typically including 6 or more sensors perregion. Providing the sensor patches 30 including memory devices 67, forexample EEPROMs, on high density sheets 200 as illustrated in FIGS. 10Athrough 10D provide the capability of calibrating and/or pre-dosing theentire sheet of sensor patches 30 at one time. As shown in FIG. 10A, thesheets 200 may include perforations for subsequent separation of theindividual sensor patches 30 from the high density sheet 200. In certainembodiments, the sheet of sensor patches 200 may include from about 30to about 100 sensor patches 30 per sheet. In other embodiments, multiplepatches 30 may be provided per square inch of the high-density sheet 200and/or multiple patches 30, typically at least 6 patches, may beprovided in a 3 by 3 inch region of the high-density sheet.

[0138] As further illustrated in FIG. 10D, in some embodiments of thepresent invention, the sensor patches 30 may be configured in an array200′ of 16×2 sensor patches. This arrangement may provide a method ofprocessing 32 patches in a single batch. Each patch may be singularized,i.e., detached from the other sensor patches 30 in the batch, in thefinal processing steps. In some embodiments of the present invention,the dimensions of the array may be selected so that the sheet fitswithin a 6″ diameter cylinder, such as a cylindrical blood irradiatorchamber. The final assembly may be calibrated using a researchirradiator, blood irradiator, LINAC or other radiotherapy equipmentwithout departing from the teachings of the present invention. It willbe understood that calibration techniques known to those having skill inthe art may be used to calibrate the patches 30 according to someembodiments of the present invention.

[0139] The sensor patches 30 may be calibrated at the factory or OEM.Each of the sensor patches 30 or the entire sheet 200 of sensor patches30 may be calibrated by providing a wire(s) 205 illustrated in FIG. 10Bthat electrically couples each of the sensor patches 30 on the sheet200. For ease of reference, only a single electrical line to one sensoris shown on FIG. 10B. The calibration data may be provided to the sensorpatches 30 through the wire(s) 205 and may be stored in the memorystorage device 67 of the sensor patch 30. The ability to calibrate aplurality of sensor patches 30 simultaneously may provide more precisionin the dosimetry process and, therefore, possibly more reliable results.It will be understood that the sensor patches 30 may each have adedicated wire or the sheet can have a calibration line all connected toa common lead 206 as shown in FIG. 10C that may be used to calibrateand/or pre-dose the sensor patches 30 individually.

[0140] As discussed above, the sensor patches 30 may be pre-dosed, i.e.dosed prior to placement on the patient. Dosing a sensor patch mayinclude, for example, setting the amount of radiation to be delivered toa patient and the particular region(s) on the patient to which theradiation should be delivered. This process is typically performed by aphysicist and can be very time consuming. The possibility of accuratelypre-dosing a sensor patch 30 may significantly reduce the need for aphysicist to be involved in the dosimetry confirmation process. In otherwords, using reliable dose patches can reduce the time a physicistexpends to confirm the treatment beam and path dose.

[0141] It will be understood that sensor patches 30 adapted to bereceived by a reader 75 are not limited to the configuration illustratedin the figures provided herein. These figures are provided for exemplarypurposes only and are not meant to limit the present invention. Forexample, the sensor patch 30′ of FIG. 9B can be configured with ageometry that allows it (entirely or partially) to be received by areader 75″. The insertable geometry may take the form of an elongatedtab, one end of the tab containing the radiation sensitive circuitry aswell as the memory and the other end of the tab containing theelectrical contacts for insertion into the reader device (not shown).

[0142] Some embodiments of the present invention provide a test strip2200 as illustrated in FIG. 22. The test strip 2200 may allow thefunctionality and calibration of the reader 75 to be tested andverified. According to some embodiments of the present invention, thetest strip 200 may consist of a sensor patch including an EEPROM and aresistor and a voltage reference instead of the MOSFET/RADFET. Thus, inthe event that the reader 75 is, for example, left in the radiationtreatment beam, has a mechanical failure or the like, a 4.096 Vreference or a current source may be altered and, therefore, may yieldincorrect dose readings. The test strip 2200 may provide an externalreference that may be used to verify proper operation and calibration ofthe reader 75.

[0143] As stated above, the test strip 2200 may be similar to the sensorpatch 30 except the RADFET may be replaced with a series combination ofa voltage reference and a resistance, for example, a 1.2V shuntreference (specified at 0.1% tolerance such as an LM4051-1.2) and a 10KΩ resistor (0.1% tolerance). In some embodiments of the presentinvention, the gate/drain connection may have a 39 Kg, 0.1% toleranceresistor coupled to ground on the test strip 2200. The 39 KΩ resistormay provide an additional 52 μA bias to the series 1.2V reference and 10KΩ resistor.

[0144] The test strip 2200 may include a memory map, which may include,among other things, the defaults from the base load (at the ZTCprocess), i.e. the pre-radiation data. Table 7 of FIG. 31 contains alisting of functional specifications of test strips according to someembodiments of the present invention. It will be understood that thefunctional specifications listed in FIG. 31 are provided for exemplarypurposes only and that embodiments of the present invention are notlimited to this configuration.

[0145] The reader 75 may interrogate the test strip memory and requestthat a doctor technician perform a “zeroing operation” discussed furtherbelow. The test strip 2200 may be zeroed and the resulting digital toanalog conversion (DACB) value may be compared to the DACB valuedetermined at the factory. The result may indicate, for example, “ReaderOK” if the DACB value is within a set of limits provided or “Readerneeds Cal” if the DACB value is outside the set of limits. It will beunderstood that the limits may be determined on a per-reader basisduring factory calibration.

[0146] In certain embodiments of the present invention, the test strip2200 may be configured to prevent modification by the reader 75. In someembodiments of the present invention, the reader may be configured toindicate “Reader OK” when the test strip 2200 is inserted and apredetermined reference voltage, such as about 4.096 V, is within apredetermined range. The reader may be further configured to indicate“Reader needs Cal” if the reference voltage is outside of thepredetermined range. In some embodiments of the present invention, thepredetermined range may be from about 4.075 to about 4.116V. Thetolerance on the limits may be about ±0.005V

[0147] As shown in FIG. 11, in certain embodiments, the patch radiationsensitive device 63 is a RADFET. The RADFET can be biased with agate/drain short so that it acts as a two-terminal device. FIG. 11illustrates a portion of the circuit 30 c with a RADFET 63 and twoassociated reader 75 interface or contact points 63I₁, 63I₂. FIG. 12Aillustrates a reader 75 (upper broken line box) and the circuit 30 c(lower broken line box) with the RADFET 63 configured with a gate todrain short. As shown, the reader 75 can include a RADFET bias circuit75 b that includes a controlled current source to allow a voltagereading to be obtained corresponding to the threshold voltage of theRADFET.

[0148] As shown by the graph in FIG. 12B, changes in surface statecharge density induced by ionizing radiation causes a shift in thresholdvoltage in the RADFET. FIG. 12B illustrates a radiation response of astandard P210W2 400 nm implanted gate oxide RADFET with lines for 0V(the -0- marked line) and 5V (the line with the -*- markings)irradiation bias responses. To obtain the amount of threshold voltage(“Vth”) shift, the Vth value (zero dose) can be subtracted from thepost-irradiation value and the calibration curve used to determineradiation dose. The calibration curve can be pre-loaded into thecontroller of the reader or a computer to provide the dose data. Incertain embodiments, when obtaining the readings, the clinician may weargrounding straps to reduce static sensitivity of the circuitry. Incertain embodiments, such as where contact points are exposed, ESDprotection may be integrated into the sensor patch 30 itself.

[0149] As shown in FIG. 12A, the Vth change can be measured bydetermining the change in applied gate voltage necessary to induce a setcurrent flow. As noted above, the RADFET characterization data can beobtained prior to exposure to radiation (zero dose). Thus, the startingthreshold voltage of the sensor patch 30 will be known from a prioriinformation (or can be obtained by the clinician prior to placing on thepatient or after on the patient but before radiation exposure) and canbe placed in the reader 75 or computer associated or in communicationtherewith.

[0150]FIG. 13 illustrates the threshold voltage relationship betweenoutput voltage (voltage) and current Ids (the electrical current,drain-to source, in microamps) as measured using the output voltage ofthe reader circuit shown in FIG. 12A. In operation, the reader circuitis configured to contact the sensor to provide a constant current sourceto the circuit so as to be able measure Vth at a substantially constantor fixed bias condition.

[0151] In some embodiments of the present invention, the zerotemperature coefficient of the MOSFET/RADFET 63 (FIG. 11) may beobtained. The zero temperature coefficient of a MOSFET refers to aspecific bias current level at which the threshold voltage of the MOSFETdoes not change significantly with temperature variation in the range oftemperatures likely to be encountered according to some embodiments ofthe present invention. Although the zero temperature bias currenttypically varies from one MOSFET to another, it is a parameter that maybe measured before the administration of radiation therapy to thepatient and stored, for example, in the memory device 67, along with thepre-radiation threshold voltage of the MOSFET measured when the MOSFETis biased with the zero temperature bias current. After recording andstoring these parameters, the patch 30 may be exposed to radiation andinserted into the reader 75 or wirelessly coupled to the reader 75. TheMOSFET may be biased with the stored zero temperature bias current(which the reader 75 may obtains from the memory device 67) and thepost-radiation threshold voltage of the MOSFET may be measured. Thechange in the threshold voltage, i.e., the difference between thepre-radiation threshold voltage and the post-radiation thresholdvoltage, may be used by the reader 75 to calculate the radiation dose.It will be understood that in these embodiments of the present inventionthe MOSFET is not operated in a biased configuration or otherwisepowered during the radiation treatment session.

[0152] The memory device 67 on the patch 30 may include a memory mapidentifying memory locations and contents thereof. In some embodimentsof the present invention, the memory map may resemble a spreadsheet. Thememory map may include one or more fields containing data, such asserial numbers, calibration factors, dose records, time stamps, biasingparameters, factory calibration information and the like. The reader 75may access data stored in the memory map using, for example, a standard12C protocol as discussed further below. Details with respect to memorymaps will be understood by those having skill in the art and will not bediscussed further herein.

[0153] In some embodiments of the present invention, the dose may becalculated using Equation 1 set out below:

Dose=k _(energy) *k _(rate) *k _(SSD) * k _(fieldsize) *k _(temp) *k_(wedge) *k _(fade) *[a(v _(shift))³ +b(v _(shift))² +c(v_(shift))+d]  (Equation 1)

[0154] V_(shift) is the voltage difference (as seen by the 24-bit A/Dconverter) between the pre-radiation and post-radiation thresholdvoltage when measured at the zero temperature coefficient current(I_(BiasZTC)) discussed below. k_(energy) (Energy), k_(rate) (DoseRate), k_(SSD), k_(fieldsize) (Field Size), k_(temp) (Temperture),k_(wedge) (Wedge Angle), k_(fade) (Fade Time) (See FIG. 25) and/or othercorrection factors (collectively the “k-factors”) may be stored inmemory locations of the memory map stored in the electronic memory 67.In some embodiments of the present invention, if a coefficient isrequired, the reader can prompt the user for the coefficient during thezeroing operation. A calibration curve illustrating a dose response ofan exemplary MOSFET/RADFET according to some embodiments of the presentinvention is provided in FIG. 23. It will be understood that thecalibration curve provided in FIG. 23 is provided for exemplary purposesonly and that embodiments of the present invention are not limited bythis example.

[0155] As necessary, correction factors may be applied for energy, doserate, field size, temperature, wedge factors, fading or otheruser-defined corrections. The reader 75 can be configured to provideautomatic prompts to a user or an equipment operational station toobtain the desired patient-specific and/or equipment inputs (i.e., userinput calibration factors). Coefficients for the correction factors maybe stored in the electronic memory 67 of the patch 30. User correctionfactors may also be stored in the reader 75 non-volatile memory and maybe copied into the electronic memory 67 of the patch 30 as a record ifthe correction factors are used in the dose calculation. A graph set outin FIG. 24 illustrates and an exemplary correction factor for energydependence. It will be understood that the graph provided in FIG. 24 isprovided for exemplary purposes only and that embodiments of the presentinvention are not limited by this example.

[0156] Referring to FIG. 24, the correction factors are curve-fitted toa 3rd-order polynomial and the coefficients may be stored in the memorycell locations of the memory map in the electronic memory 67 of thepatch 30. In some embodiments of the present invention, the defaultvalues may be 0, 0, 0, 1 for a, b, c, and d, respectively. Table 2 ofFIG. 25 sets out exemplary “k-factors”, discussed above, that may beapplied to the dose equation set out in Equation 1 above.

[0157] In particular, temperature correction factor coefficients may bestored in the memory locations of the memory map stored in theelectronic memory 67 of the patch 30. In some embodiments of the presentinvention, the temperature correction factor coefficients may be storedin a floating point format. The coefficients may be stored in the orderillustrated in Table 3 of FIG. 26 illustrating temperature correctioncoefficient locations.

[0158] The standard temperature may be normalized to about 20° C. Thecorrection factors may be curve-fitted to a 3rd-order polynomial and thecoefficients may be stored in the memory map of the patch 30. Thedefault values may be, for example, set to 0, 0, 0, 1 for a, b, c, andd, respectively. The input to the equation may be the temperature in °C. determined by calculating the temperature (° C.). This is calculatedfrom the difference in a diode reference voltage and a diode voltagemeasured during the post-radiation process. The difference may bemultiplied by the diode temperature coefficient stored in the memory 67and added to 27° C. plus {fraction (1/10)}th of T_(Offset) discussedbelow.

[0159] For example, the patch temperature may be determined according toEquations 2 and 3 set out below:

V _(Diode)=2.048−(V _(ADC) _(—) _(Diode)−800000h)*4.096/224   (Equation2)

Temperature=27+10*(T _(offset))+(V _(Diode)−Diode VoltageReference)/Temp Coeff. of the Diode   (Equation 3)

[0160] Furthermore, fade correction factor coefficients, i.e.,coefficients of the correction factors for fading of the RADFET voltage,may be stored in the memory locations of the memory map stored in theelectronic memory 67 of the patch 30. In some embodiments of the presentinvention, the fade correction factor coefficients may be stored in afloating point format. The coefficients may be stored in the orderillustrated in Table 4 of FIG. 27 illustrating fade correctioncoefficient locations.

[0161] The standard time may be normalized to about 300 seconds (5minutes). The correction factors may be curve-fitted to a 3rd-orderpolynomial and the coefficients may be stored in the respectivelocations in the patch memory 67. The default values may be set to 0, 0,0, 1 for a, b, c, and d, respectively. The input to the dose equation(Equation 1) is the difference in time (seconds) between the Dose-Endtimestamp and the Reading Time versus the 300 second normalized time.For example, if the reading takes place 5 minutes and 30 seconds afterthe dose end time, the input to the dose equation (Equation 1) would be30 seconds. If the reading takes place 4 minutes after the dose endtime, then the input to the equation would be −60 seconds.

[0162] In some embodiments of the present invention, the user may beprompted to input, such as via a touch sensor or a keypad, to indicatethe end of the dose treatment. If there are multiple fields of radiationinvolved, the user may be instructed to press the timestamp buttonduring the last treatment field. The time difference may be calculated(in seconds) between the dose end time and the reading time and may beused to correct for fade. If the prompt for dose time is not configured(in the reader) then the Zero-reading time plus 300 seconds may be usedas the dose end time. A graph set out in FIG. 28 illustrates anexemplary response for fade in the RADFET voltage following a doseapplication.

[0163] The cells of the memory map may further include a standardizedhex-coded D/A Converter value that may be used to bias the RADFET 63 tothe factory-determined zero temperature bias current (ZTC). The value ofthe ZTC current may be determined at the factory and may be stored inthe memory device 67 during the calibration process for each individualsensor. The value that may be stored in the memory device 67 is the D/Avalue and would be written if the particular reader reference voltages,D/A (assume 16-bit), resistor values, offset voltages and bias currentsare ideal. For example, if the factory determined ZTC current is:

i_(Bias) _(—) _(ZTC)=10.00 μA   (Equation 4)

[0164] The value of the ZTC current stored in the memory device67(I_(BiasZTC)) during the calibration process for each individualsensor may be calculated using Equation 5 set out below.

I _(BiasZTC)=((V _(4.096) −i _(Bias) _(—) _(ZTC) *R _(Bias))/V_(4.096))*2¹⁶   (Equation 5)

[0165] In some embodiments of the present invention, the parameters usedin this calculation may be: V_(4.096)=4.096 V, V_(2.048)=2.048 V andR_(Bias)=10.00 KΩ. Inserting these values into Equation 5, I_(BiasZTC)may be 79 C0_(H).

[0166] The actual DAC value that may be used for a particular reader 75depends on the reader calibration coefficients. The actual DAC value maybe adjusted so that the effects of the non-ideal, such as 4.096 and2.048 VDC references, 10.00 KΩ resistor, op-amp input offset voltageand/or bias current of each particular reader 75 may be corrected. Insome embodiments of the present invention, the reader calibrationcoefficients for the I_(BiasZTC) current are “I_(Bias) _(—) _(Offset)”and “I_(Bias) _(—) _(Gain)” as may be stored in a memory location of thereader 75 and may be determined during factory calibration. The actualvalue written to a particular reader DAC may be calculated usingEquation 6 set out below:

Ibias-ztc _(reader(x)) =I _(BiasZTC) *I _(Bias) _(—) _(Gain) +I _(Bias)_(—) _(Offset)   (Equation 6)

[0167] Table 5 of FIG. 29 includes exemplary V/I relationships ofreaders determined during calibration according to some embodiments ofthe present invention. It will be understood that the V/I relationshipsset out in Table 5 are provided for exemplary purposes only andembodiments of the present invention are not limited to thisconfiguration.

[0168] In some embodiments of the present invention, the bias currentaccuracy for any individual reader 75 may be specified at about ±φnA.The trans-conductance of the RADFET may be specified at about {fraction(1/100)} KΩ max at the ZTC bias current. If the bias current changesbetween the “pre-radiation” and “post-radiation” dose readings due to,for example, switching readers, there may be a potential voltage errorof about 100 nA*100 KΩ=10 mV. Since the initial sensitivity of theRADFET may be specified at about 0.25 mV/cGy, this represents apotential 40 cGy error. The specified error for the system may be about±1 cGy for a 20 cGy dose. The repeatability of the bias current (between“pre” and “post” dose measurements) on an individual reader 75 may bespecified at about ±1 nA so that the error due to a “trans-conductanceeffect” may be limited to about 1 nA*100 KΩ=100 μV.

[0169] The reader 75 may initially “zero” an un-dosed sensor patch 30 byadjusting the output of a digital to analog converter (DAC) so that theanalog to digital (A/D) converter input is near zero. The DAC is thestandardized bias current setting that may be used for the A/D readingsfor the pre-radiation and post-radiation threshold voltage measurements.The “zeroed” value may be stored in the electronic memory 67 and thepatch status register may be updated to indicate that the patch has been“zeroed”. The zeroing operation may limit the range of the RADFET biascurrent source. After the patch has been dosed and reinserted, thereader 75 may reset the DAC-B channel to a previous level using datastored in the memory location of the electronic memory 67 so that thevoltage measured by the A/D converter may represent the shift in voltagedue to radiation. The scaling may be arranged in hardware so that thevoltage generated by the DAC-B is approximately ⅓ of the thresholdvoltage at the RADFET. The A/D conversion result and the standardizedbias current (DAC or DAC-A) may be stored in cells of the electronicmemory 67.

[0170] The Digital-to-Analog Converter (DAC) may provide two functions.The first is to establish the bias current in the RADFET based on afactory-derived bias current setting. This current may be established sothat there is a minimum influence of temperature on the RADFET thresholdvoltage. The second DAC, OFFSET DAC, may provide a means to offset theRADFET initial threshold voltage in the “zeroing” procedure. In otherwords, prior to dosing, the patch may be zeroed by adjusting the OFFSETDAC so that the output of the summing amplifier is about 2.048V±100 mVwhen the patch RADFET is connected. The summing amplifier subtracts thevoltage from the OFFSET DAC from the RADFET and applies the differenceto the A/D Converter. This DAC setting may be stored in electronicmemory 67 of the patch 30 and reused after dose is applied to bias theRADFET. The difference in the pre-dose and post-dose RADFET thresholdvoltages measured by the A/D Converter may be used to calculate themeasured dose.

[0171] The memory map may also include a memory cell includingT_(offset), which may be, for example, a byte representing thetemperature at which the diode voltage of the RADFET may be measured. Insome embodiments of the present invention, the offset may be based on anominal temperature of about 27.0° C. Accordingly, if, for example, theactual temperature during the RADFET diode measurement (during the ZTCprocess) is 27.0° C., then the offset will be 00h.

[0172] In some embodiments of the present invention, the diode voltagemay be measured (at the I_(Bias) _(—) _(Diode) current) during ZTCprocessing and the voltage may be converted to hexadecimal notationusing Equation 7 set out below.

V _(Diode@Temp)=800000h+(2.048−V _(Diode(measured)))*2²⁴/4.096  (Equation 7)

[0173] This value may be stored in memory locations of the memory map inthe electronic memory 67.

[0174] As noted above, the MOSFET bias parameters, along with customizedcalibration coefficients, are stored in the EEPROM memory provided oneach patch. The patch memory also includes a patch identifier or serialnumber, and instructions on how the reader interfaces with the patch.Provision of these instructions allows the reader to work with multiplegenerations of patches without necessitating upgrades to the reader. Thepatch memory also stores the detected and calculated radiation dosages,the date and time of the treatment, and a clinician-entered patientidentifier and/or record number. After use, the patch can be placed inthe patient file or medical record to form a part of the archivedpatient treatment history, or may be discarded.

[0175]FIGS. 14A and 14B illustrate alternate embodiments of MOSFET basedcircuits 30 c. Each circuit 30 c employs a RADFET pair 63 p (FIG. 14A),63 p′ (FIG. 14B) as the radiation sensitive device 63. The configurationon the left of each of these figures illustrates the irradiationconfiguration and the configuration on the right illustrates the readdose configuration. In the embodiment shown in FIG. 14A, the RADFET pair63 p are differentially biased during irradiation to create differentvoltage offsets. Each of the RADFETs in the pair 63 p ₁, 63 p ₂ can bedifferentially biased during radiation to generate different voltageoffsets when exposed to radiation. Using a pair of RADFETS can reducethe influence of temperature in the detected voltage shift value. Inparticular embodiments, the RADFET pair can be matched (such as takenfrom the same part of the substrate during fabrication) to reduce drifteffects (Vth drift). In certain embodiments, the voltage reading can beobtained with a zero bias state, and/or without requiring wires duringradiation, and/or without requiring a floating gate structure.

[0176] In the embodiment shown in FIG. 14B, one of the RADFETs 63 p ₁′in the pair 63 p is selectively implanted with dopant ions to shift thethreshold voltage (Vth) of that RADFET with respect to the other RADFET63 p ₂′. The ion implantation can be carried out in various manners asknown to those of skill in the art, such as by masking one of the FETswith photoresist to inhibit ions from entering into the gate region. Asis well known, using the proper implant species and/or dopant materialcan increase the FET sensitivity to radiation effects. In certainembodiments of the present invention, a MOSFET (RADFET) pair is used toeffectively provide “differential biasing” without the need to apply anexternal voltage and without the need for a floating gate structure.That is, the MOSFETs can be configured to be individually unbiased andreadings of the two MOSFETs (one at a different threshold voltage value)generates the differential biasing. In particular embodiments, thisradiation sensitive MOSFET pair configuration that does not requirefloating gate structures and/or external voltage can be used inimplantable as well as skin mounted sensors, such as in implantablesensors used as described in U.S. Pat. No. 6,402,689 to Scarantino etal.

[0177]FIG. 15A illustrates embodiments of a radiation dose evaluationsystem 15 according to embodiments of the present invention. As shown,the system 15 includes a reader 75 and a set of radiation sensor patches130′. The reader 75 may include, for example, the reader 75′ of FIG. 15Bor the reader 75″ of FIG. 15C. The sensor patches 30 can be arranged asa strip of patches 30 held in a single-patient sized package 130 p. Asbefore, the package 130 p may also include bar coded radiationcalibration characterizing data labels 132 for the sensor patches 30and/or a memory 167 in each or selected memory patches 30. The reader75′ as shown in FIG. 15B can include the probe 75 p, an optical wand 75w and a display screen 75 d. The reader 75″ as shown in FIG. 15C caninclude a sensor port 32 and a display screen 75 d. The reader 75 canalso include a RADFET bias circuit 75 b. In certain embodiments, thereader 75 is a portable flat pocket or palm size reader that a cliniciancan carry relatively non-obtrusively in his/her pocket or a similarsized casing.

[0178] As shown by the dotted line boxes in FIG. 15A, the reader 75 mayhold a power source 78 and plurality of operational software modulesincluding: an optical bar code reader module 76, a zero-dose thresholdvoltage data module 77, a radiation dose conversion module (based on apredetermined voltage threshold to radiation dose response curve) 79,and a threshold voltage post radiation data module 80.

[0179] In operation, the reader 75 can be configured to supply a biascurrent to the RADFET by attaching to the sensor patch 30 andelectrically contacting the conductive probe region 30 p or theelectrical contacts 31. The reader 75 can measure the voltage shiftresponse of the RADFET on the sensor patch 30 and calculate radiationdose based on the shift and the dose conversion algorithm. The reader 75can display the results to the clinician (such as on an integrated LCDscreen 75 d incorporated into the body of the reader) and may beconfigured to download or upload the data to another device (such as acomputer or computer network) for electronic record generation orstorage.

[0180] The reader may include an electronic memory map identifyingmemory locations and contents thereof. In some embodiments of thepresent invention, the memory map may resemble a spreadsheet. The memorymap may include one or more fields containing data, such as serialnumbers, revision number, reader calibration data, AID gain correction,A/D offset correction, D/A gain correction, D/A offset correction,hospital ID and the like. In some embodiments of the present invention,the reader memory may be large enough to store 250 dose records of about64 bytes each. The dose record may include items listed in Table 6 ofFIG. 30. It will be understood that the dose record of FIG. 30 isprovided for exemplary purposes only and embodiments of the presentinvention should not be limited to this configuration. Details withrespect to memory maps will be understood by those having skill in theart and will not be discussed further herein.

[0181] The dose amount can be calculated for each sensor patch 30 used.In particular embodiments, the system can be configured to generate anaverage or weighted average of the dose amount determined over aplurality of the patches. In certain embodiments, where there is a largevariation in values (or if it departs from a statistical norm orpredicted value) the system can be configured to discard that sensorvalue or to alert the clinician of potential data corruption. Of course,much smaller values are predicted in sensitive areas away from thetargeted zone and the system can be configured to evaluate whether thesensor is in a primary location or in a secondary zone as regards theradiation path.

[0182] It is noted that features described with respect to oneembodiment of the sensor, reader and/or system may be incorporated intoother embodiments and the description and illustrations of such featuresare not be construed as limited to the particular embodiment for whichit was described.

[0183] As will be appreciated by one of skill in the art, the presentinvention may be embodied as a method, data or signal processing system,or computer program product. Accordingly, the present invention may takethe form of an entirely hardware embodiment or an embodiment combiningsoftware and hardware aspects. Furthermore, the present invention maytake the form of a computer program product on a computer-usable storagemedium having computer-usable program code means embodied in the medium.Any suitable computer readable medium may be utilized including harddisks, CD-ROMs, optical storage devices, or magnetic storage devices.

[0184] The computer-usable or computer-readable medium may be, forexample but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, device,or propagation medium. More specific examples (a non-exhaustive list) ofthe computer-readable medium would include the following: an electricalconnection having one or more wires, a portable computer diskette, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,and a portable compact disc read-only memory (CD-ROM). Note that thecomputer-usable or computer-readable medium could even be paper oranother suitable medium upon which the program is printed, as theprogram can be electronically captured, via, for instance, opticalscanning of the paper or other medium, then compiled, interpreted orotherwise processed in a suitable manner if necessary, and then storedin a computer memory.

[0185] Computer program code for carrying out operations of the presentinvention may be written in an object oriented programming language suchas LABVIEW, Java®, Smalltalk, Python, or C++. However, the computerprogram code for carrying out operations of the present invention mayalso be written in conventional procedural programming languages, suchas the “C” programming language or even assembly language. The programcode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer. In the latter scenario, the remote computer may be connectedto the user's computer through a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).

[0186]FIG. 16 is a block diagram of exemplary embodiments of dataprocessing systems that illustrate systems, methods, and computerprogram products in accordance with embodiments of the presentinvention. The processor 310 communicates with the memory 314 via anaddress/data bus 348. The processor 310 can be any commerciallyavailable or custom microprocessor. The memory 314 is representative ofthe overall hierarchy of memory devices containing the software and dataused to implement the functionality of the data processing system. Thememory 314 can include, but is not limited to, the following types ofdevices: cache, ROM, PROM, EPROM, EEPROM, flash memory, SRAM, and DRAM.

[0187] As shown in FIG. 16, the memory 314 may include severalcategories of software and data used in the data processing system 305:the operating system 352; the application programs 354; the input/output(I/O) device drivers 358; a radiation estimator module 350; and the data356. The data 356 may include threshold voltage data 340 (zero dose andpost irradiation dose levels) which may be obtained from a reader dataacquisition system 320. As will be appreciated by those of skill in theart, the operating system 352 may be any operating system suitable foruse with a data processing system, such as OS/2, AIX, OS/390 orSystem390 from International Business Machines Corporation, Armonk,N.Y., Windows CE, Windows NT, Windows95, Windows98, Windows2000 orWindows XP from Microsoft Corporation, Redmond, Wash., Unix or Linux orFreeBSD, Palm OS from Palm, Inc., Mac OS from Apple Computer, orproprietary operating systems. The I/O device drivers 358 typicallyinclude software routines accessed through the operating system 352 bythe application programs 354 to communicate with devices such as I/Odata port(s), data storage 356 and certain memory 314 components and/orthe image acquisition system 320. The application programs 354 areillustrative of the programs that implement the various features of thedata processing system 305 and preferably include at least oneapplication that supports operations according to embodiments of thepresent invention. Finally, the data 356 represents the static anddynamic data used by the application programs 354, the operating system352, the I/O device drivers 358, and other software programs that mayreside in the memory 314.

[0188] While the present invention is illustrated, for example, withreference to the radiation estimator module 350 being an applicationprogram in FIG. 16, as will be appreciated by those of skill in the art,other configurations may also be utilized while still benefiting fromthe teachings of the present invention.

[0189] For example, the radiation estimation module 350 may also beincorporated into the operating system 352, the I/O device drivers 358or other such logical division of the data processing system. Thus, thepresent invention should not be construed as limited to theconfiguration of FIG. 16, which is intended to encompass anyconfiguration capable of carrying out the operations described herein.

[0190] In certain embodiments, the radiation estimation module 350includes computer program code for estimating radiation dose based onthe measured threshold voltage shift. The I/O data port can be used totransfer information between the data processing system and the readerdata acquisition system 320 or another computer system or a network(e.g., the Internet) or to other devices controlled by the processor.These components may be conventional components such as those used inmany conventional data processing systems that may be configured inaccordance with the present invention to operate as described herein.

[0191] While the present invention is illustrated, for example, withreference to particular divisions of programs, functions and memories,the present invention should not be construed as limited to such logicaldivisions. Thus, the present invention should not be construed aslimited to the configurations illustrated in the figures but is intendedto encompass any configuration capable of carrying out the operationsdescribed herein.

[0192] The flowcharts and block diagrams of certain of the figuresherein illustrate the architecture, functionality, and operation ofpossible implementations of radiation detection means according to thepresent invention. In this regard, each block in the flow charts orblock diagrams represents a module, segment, or portion of code, whichcomprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that in somealternative implementations, the functions noted in the blocks may occurout of the order noted in the figures. For example, two blocks shown insuccession may in fact be executed substantially concurrently or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved.

[0193]FIG. 17 is a block diagram illustration of one embodiment of areader 75 according to the present invention. As shown, the reader 75includes an operating system 422, a processor 410, a power source 456,and a user activation /input module 460. The reader 75 can also includea RADFET interface module 475 and a sensor patch memory interface module478. The reader 75 may communicate with the sensor patch memory using,for example, a standard 12C protocol and in some embodiments may use aclock as a data line. As discussed above, in certain embodiments, thesensor patch 30 may be configured to communicate wirelessly with thereader 75. In these embodiments, the interface module 475 may beconfigured to receive wireless signals from the sensor patch 30. Thereader 75 may optionally include a sensor patch identifier module 428 totrack which sensor patch 30 has a particular radiation dose result. Theidentifier module 428 may allow the user to input via an input keypadassociated with the reader, an alphanumeric identifier (F1, B1, etc.)for a particular sensor patch prior to obtaining the reading, or a barcode identifier or other automated identifier means can be used (such asscanning a bar code label on the sensor and the like). The reader 75also includes pre-radiation (zero dose) threshold voltage data 440, postradiation threshold voltage data 441, and a radiation estimation module458. The pre-radiation threshold voltage data 440 and the post radiationthreshold data 441 may be obtained when the MOSFET is biased with thezero temperature bias current discussed above. The zero temperature biascurrent may be obtained before the administration of the radiationtherapy, stored in the sensor patch memory 67 (FIG. 11) and obtained bythe reader using the sensor patch memory interface module 478. Theradiation estimation module 458 may also be configured to extrapolate toarrive at the radiation dose delivered to the tumor site. In someembodiments of the present invention, the radiation estimation module458 may be further configured to prompt a doctor or technician forpredetermined data needed to calculate or estimate the radiation dose.The predetermined data may include conversion factors and/or correctionfactors associated with different versions of the sensor patches. Asshown, the reader 75 may also include an optical bar code scanner module476 to allow the reader to input the characterizing zero dose thresholdvoltage values by optically reading same. Similarly, calibration datacan be entered via the bar the bar code scanner 476 or memory 67 fromthe patches 30. Alternatively, the clinician can enter the desired datain situ as desired.

[0194] Tables 8 and 9 of FIGS. 32 and 33 contain a listing thefunctional specification of readers and sensor patches, respectively,according to some embodiments of the present invention. It will beunderstood that the functional specifications listed in FIGS. 32 and 33are provided for exemplary purposes only and that embodiments of thepresent invention are not limited to this configuration.

[0195] Although primarily described for oncologic therapies, the devicescan be used to monitor other radiation exposures, particularly exposuresduring medical procedures, such as fluoroscopy, brachytherapy, and thelike.

[0196] The foregoing is illustrative of the present invention and is notto be construed as limiting thereof. Although a few exemplaryembodiments of this invention have been described, those skilled in theart will readily appreciate that many modifications are possible in theexemplary embodiments without materially departing from the novelteachings and advantages of this invention. Accordingly, all suchmodifications are intended to be included within the scope of thisinvention as defined in the claims. In the claims, means-plus-functionclauses, where used, are intended to cover the structures describedherein as performing the recited function and not only structuralequivalents but also equivalent structures. Therefore, it is to beunderstood that the foregoing is illustrative of the present inventionand is not to be construed as limited to the specific embodimentsdisclosed, and that modifications to the-disclosed embodiments, as wellas other embodiments, are intended to be included within the scope ofthe appended claims. The invention is defined by the following claims,with equivalents of the claims to be included therein.

That which is claimed is:
 1. A method for monitoring radiationadministered to patients undergoing radiation a therapeutic treatment,comprising the steps of: releasably securing at least one single-usedosimeter sensor patch comprising electronic memory to be in intimatecontact with the skin of the patient such that, during irradiation, thepatch is self-contained; obtaining data associated with a change in anoperational parameter in the at least one patch electronic memory usinga dose reader, the patch electronic memory being configured with dataincluding instructions that direct how the dose reader communicates withthe at least one patch and/or obtains data stored in the patchelectronic memory; and determining a radiation dose received by thepatient based on the obtained data of the change in the operationalparameter.
 2. The method of claim 1 wherein obtaining data from theelectronic memory comprises wirelessly obtaining data from the patchelectronic memory on the at least one patch using the dose reader. 3.The method of claim 1 wherein an underside of the at least one patchcomprises an adhesive, and wherein the releasably securing step iscarried out by pressing the patch onto the skin so that it conformablyadheres thereto.
 4. The method of claim 3 further comprising providing abuildup cap on the surface of the at least one patch to simulate asubsurface placement of the at least one patch corresponding to a depthDmax at which an absorbed dose reaches a maximum for a given energy. 5.The method of claim 4 wherein Dmax corresponds to a distance of fromabout 1 to about 3 cm beneath the skin of the patient.
 6. The method ofclaim 4 wherein the buildup cap is configured to attach onto the atleast one sensor patch, and wherein the lower primary surface of thebuildup cap comprises a medical grade adhesive thereon.
 7. The method ofclaim 4 wherein the buildup cap comprises molded polystyrene and a layerof copper on the molded polystyrene.
 8. The method of claim 1 whereinreleasably securing the sensor patch onto the skin of the patient ispreceded by: at least one of calibrating and/or pre-dosing the at leastone patch; and storing patch specific calibration data in the patchelectronic memory of each respective at least one patch.
 9. The methodof claim 1 further comprising storing radiation-dose data, patient data,time and date of radiation reading, and/or calibration data in the patchelectronic memory of the at least one patch.
 10. The method of claim 1wherein the at least one patch comprises a MOSFET device with anassociated threshold voltage which changes when exposed to radiation,wherein the threshold voltage is the operational parameter, wherein apost-radiation threshold voltage value of the MOSFET device and apre-radiation threshold voltage value of the MOSFET device are stored inthe patch electronic memory and wherein the determining step furtherincludes analyzing the change in the threshold voltage based on thestored post-radiation threshold voltage value and the storedpre-radiation threshold voltage value of the MOSFET device.
 11. Themethod of claim 10 wherein releasably securing the at least one patch isfollowed by administering therapeutic radiation to the patient.
 12. Themethod of claim 11 further comprising: measuring a zero temperaturecoefficient of the MOSFET prior to securing the patch on the patient;and storing the zero temperature coefficient of the MOSFET in the patchelectronic memory.
 13. The method of claim 12 further comprising:measuring the pre-radiation threshold voltage value of the MOSFETdevice; biasing the MOSFET using the stored zero temperature coefficientafter the administering of therapeutic radiation to the patient;measuring the post-radiation threshold voltage value of the MOSFETdevice; and automatically calculating the radiation dose based on thechange in threshold voltage of the MOSFET based on the pre-radiationthreshold voltage value and the post-radiation threshold voltage value.14. The method of claim 10 wherein the MOSFET is not biased during theadministration of therapeutic radiation to the patient.
 15. The methodof claim 10 wherein determining a radiation dose further comprisesautomatically reducing the post-radiation threshold voltage value by thepre-radiation threshold voltage value and automatically comparing to adose curve to automatically determine the radiation dose.
 16. The methodof claim 15 wherein determining a radiation dose further comprisesautomatically prompting a user of the dose reader for predetermineddata; then automatically determining the radiation dose using thepredetermined data.
 17. The method of claim 16 wherein the predetermineddata comprises a correction factor related to the at least one patch.18. An external use radiation dosimeter patch, the patch comprising: aconformable substrate having opposing upper and lower primary surfacesand holding a circuit with a MOSFET that changes an operationalparameter in a detectable predictable manner when exposed to radiationand a patch electronic memory configured with instructions on how toobtain data stored in the patch electronic memory, wherein the patch, inuse, is devoid of externally extending lead wires and wherein the patchis a single-use dosimeter patch that is adhesively securable to the skinof a patient.
 19. The patch of claim 18 wherein the lower primarysurface comprises a medical grade adhesive thereon.
 20. The patch ofclaim 18 further comprising a buildup cap on the upper primary surfaceof the patch to simulate a subsurface placement of the patchcorresponding to a depth Dmax at which an absorbed dose reaches amaximum for a given energy.
 21. The patch of claim 20 wherein Dmaxcorresponds to a distance of from about 1 to about 3 cm beneath the skinof the patient.
 22. The patch of claim 20 wherein the buildup cap isconfigured to attach onto the upper primary surface of the patch andwherein the lower primary surface of the buildup cap comprises a medicalgrade adhesive thereon.
 23. The patch of claim 20 wherein the buildupcap comprises a layer of molded polystyrene and a layer of copper on thelayer of molded polystyrene.
 24. The patch of claim 18 furthercomprising a single MOSFET and wherein the patch electronic memorycomprises an electrically erasable programmable read only memory(EEPROM).
 25. The patch of claim 24 wherein the patch is at least one ofpre-dosed and/or calibrated and associated pre-dosing and/or calibrationdata is stored in the patch electronic memory.
 26. The patch of claim 18wherein the patch electronic memory further comprises radiation-dosedata, patient data, and/or time and date of radiation reading.
 27. Thepatch of claim 18 wherein the circuit is adapted to engage with areader, wherein the MOSFET is configured to withstand therapeutic dosesof radiation, wherein the operational parameter that changes comprises athreshold voltage of the MOSFET which changes when exposed to radiationand wherein the patch electronic memory is further configured tocommunicate with the reader to automatically determine and store dataassociated with administering therapeutic radiation to the patient. 28.The patch of claim 27 wherein a post-radiation threshold voltage valueof the MOSFET and a pre-radiation threshold voltage value of the MOSFETare stored in the patch electronic memory.
 29. The patch of claim 28wherein the patch electronic memory further comprises a zero temperaturecoefficient of the MOSFET prior to administering therapeutic radiationto the patient.
 30. The patch of claim 29 wherein the MOSFET isconfigured to be biased using the stored zero temperature coefficientafter the administering of therapeutic radiation to the patient.
 31. Thepatch of claim 30 wherein the MOSFET is unbiased during theadministration of therapeutic radiation to the patient.
 32. The patch ofclaim 18 wherein the patch is configured to make electrical contact withthe a reader device to obtain data associated with the administrating oftherapeutic radiation to the patient.
 33. The patch of claim 32 whereinthe patch is adapted to be received by the reader device to makeelectrical contact with the reader device.
 34. The patch of claim 18wherein the disposable patch is configured to wirelessly communicatewith a reader device to obtain data associated with the administratingof therapeutic radiation to the patient.
 35. A system for monitoringradiation administered to a patient during a therapeutic treatment, thesystem comprising: at least one single-use dosimeter patch, the patchcomprising a generally conformable body configured to, in position, bein intimate contact with skin of a patient, the patch holding a circuitwith a MOSFET, the MOSFET having an associated threshold voltage thatchanges when exposed to radiation, the body comprising opposing upperand lower primary surfaces and a patch electronic memory configured toinclude a unique patch identifier; and a portable dose-reader configuredto communicate with the at least one patch to obtain data correspondingto a dose amount of radiation exposure the at least one patch is exposedto in use.
 36. The system of claim 35 wherein the at least one dosimeterpatch is a plurality of discrete sensor patches having a conformablebody, wherein ones of the plurality of discrete sensor patches include asingle MOSFET used to detect radiation exposure and wherein the readeris configured to communicate with each respective sensor patch to obtaina pre-radiation threshold voltage value associated with the singleMOSFET prior to administering therapeutic radiation therapy to thepatient.
 37. The system of claim 35 wherein the at least one dosimeterpatch is a plurality of discrete sensor patches having a conformableresilient body, and wherein the reader is configured to wirelesslycommunicate with each respective sensor patch to obtain a post-radiationthreshold voltage value associated therewith after use administeringtherapeutic radiation therapy to the patient.
 38. The system of claim 35wherein the at least one dosimeter patch is a plurality of discretesensor patches having a conformable resilient body, and wherein thereader is configured to electrically contact each respective sensorpatch to obtain a post-radiation threshold voltage value associatedtherewith after use administering therapeutic radiation therapy to thepatient.
 39. The system according to claim 35 wherein the patch furthercomprises a single MOSFET used to detect radiation exposure, wherein thepatch electronic memory is electrically coupled to the single MOSFET,wherein the patch electronic memory is configured to further include theobtained threshold voltage measurement data, time and date of radiationmeasurement and patient data and wherein the reader is furtherconfigured to wirelessly communicate with the patch electronic memory toobtain the unique patch identifier, the obtained threshold voltagemeasurement data, the time and the date of radiation measurement and/orthe patient data.
 40. The system of claim 39 wherein the patchelectronic memory comprises an electrically erasable programmable readonly memory (EEPROM) and is configured to store measurement methodologythat can instruct the dose reader how to obtain the radiationmeasurement.
 41. The system of claim 40 wherein the patch electronicmemory further comprises a post-radiation threshold voltage value of thesingle MOSFET and a pre-radiation threshold voltage value of the singleMOSFET.
 42. The system of claim 41 wherein the patch electronic memoryfurther comprises a zero temperature coefficient of the MOSFET.
 43. Thesystem of claim 42 wherein the MOSFET is configured to be biased usingthe zero temperature coefficient and wherein the reader is configured toautomatically reduce the post-radiation threshold voltage value by thepre-radiation threshold voltage value and automatically compare a resultto a dose curve to automatically determine the radiation dose.
 44. Thesystem of claim 43 wherein the single MOSFET is unbiased during theadministration of therapeutic radiation to the patient.
 45. The systemof claim 43 wherein the reader is further configured to automaticallyprompt a user of the reader for predetermined data before determiningthe radiation dose and to automatically determine the radiation doseusing the predetermined data, the voltage data and/or the temperaturedata.
 46. The system of claim 45 wherein the predetermined datacomprises a correction factor related to the at least one sensor patch.47. The system of claim 37 wherein the patch electronic memory furthercomprises detected and/or calculated radiation doses, date and/or timestamps, and/or a clinician entered patient identifier and/or recordnumber.
 48. The system of claim 37 wherein the at least one patch isconfigured with at least one of pre-dosed and/or calibrated prior toplacing the at least one patch on the patient and wherein the pre-dosingand/or calibration data is stored in the patch electronic memory of thepatch.
 49. The system of claim 35 wherein the lower primary surface ofthe at least one patch comprises a medical grade adhesive thereon. 50.The system of claim 35 further comprising a buildup cap on a surface ofthe at least one sensor patch to simulate a subsurface placement of theat least one sensor patch corresponding to a depth Dmax at which anabsorbed dose reaches a maximum for a given energy.
 51. The system ofclaim 50 wherein Dmax corresponds to a distance of from about 1 to about3 cm beneath the skin of the patient.
 52. The system of claim 50 whereinthe buildup cap comprises a hemispherical shape and is configured toattach to the at least one sensor patch and wherein the lower primarysurface of the buildup cap comprises a medical grade adhesive thereon.53. The system of claim 50 wherein the buildup cap comprises a layer ofmolded polystyrene and a layer of copper on the layer of moldedpolystyrene. 54 The system of claim 53 wherein the copper layer has athickness of from about 0.5 to about 1 mm.
 55. The system of claim 53wherein the polystyrene has a diameter of from about 6 to about 7 mm.56. A computer program product held in a sensor patch for evaluating aradiation dose delivered to a patient during a therapy session, thecomputer program product comprising: a computer readable storage mediumhaving computer readable program code embodied in the medium, thecomputer-readable program code comprising: computer readable programcode configured to instruct a reader on how to obtain data stored inpatch electronic memory.
 57. The computer program product of claim 56further comprising computer readable program code configured withcalibration and/or pre-dose data associated with the sensor patch. 58.The computer program product of claim 57 further comprising computerreadable program code configured with radiation-dose data, patient dataand/or time and date of radiation reading.
 59. The computer programproduct of claim 56 further comprising computer readable program codeconfigured with a post-radiation threshold voltage value associated witha MOSFET device on the sensor patch and a pre-radiation thresholdvoltage value associated with the MOSFET device on the sensor patch. 60.The computer program product of claim 59 further comprising computerreadable program code configured to store a zero temperature coefficientof the MOSFET in the patch electronic memory prior to administeringtherapeutic radiation to the patient.
 61. A computer program productheld in a reader for evaluating a radiation dose delivered to a patientduring a therapy session, the computer program product comprising: acomputer readable storage medium having computer readable program codeembodied in the medium, the computer-readable program code comprising:computer readable program code configured to communicate with anelectronic memory of at least one single use dosimeter patch to obtainthreshold data corresponding to a dose amount of radiation exposure thatthe at least one sensor patch is exposed to in use; and computerreadable program code configured to prompt a user to providepredetermined data associate with the dose amount, patient data and/orclinic data.
 62. The computer program product of claim 61 furthercomprising computer readable program code configured to communicate withthe electronic memory of the at least one patch.
 63. The computerprogram product of claim 61 further comprising computer readable programcode configured to measure a zero temperature coefficient of the MOSFETprior to administration of radiation during a therapeutic procedure. 64.The computer program product of claim 63 further comprising: computerreadable program code configured to measure the pre-radiation thresholdvoltage value of the MOSFET; computer readable program code configuredto bias the MOSFET using the stored zero temperature coefficient afterthe therapeutic procedure; computer readable program code configured tomeasure the post-radiation threshold voltage value of the MOSFET device;and computer readable program code configured to automatically calculatethe radiation dose based on the pre-radiation voltage value and thepost-radiation voltage value of the MOSFET.
 65. The computer programproduct of claim 64 further comprising computer readable program codeconfigured to automatically reduce the value of the post-radiationthreshold voltage by the pre-radiation threshold voltage value andautomatically compare a result to a dose curve to automaticallydetermine the radiation dose.
 66. The computer program product of claim64 wherein the computer readable program code configured to prompt auser further comprises computer readable program code configured toautomatically prompt a user for predetermined data to automaticallydetermine the radiation dose using the predetermined data.
 67. Thecomputer program product of claim 66 wherein the predetermined datacomprises a correction factor related to the at least one sensor patch.68. A portable medical dose reader device comprising: a portablehousing; and a circuit integrated with the portable housing, the circuitbeing configured to communicate with an electronic memory of at leastone single use dosimeter patch to obtain voltage threshold datacorresponding to a dose amount of radiation exposure that the at leastone sensor patch is exposed to in use and to prompt a user to inputpredetermined data associated with the dose amount, patient data and/orclinic data.
 69. The reader of claim 68 wherein the reader is configuredto make electrical contact with the at least one single use dosimeterpatch to communicate with the electronic memory to obtain the thresholddata corresponding to the dose amount of radiation exposure the at leastone sensor patch is exposed to during the administering of therapeuticradiation.
 70. The reader of claim 69 wherein the circuit is furtherconfigured to wirelessly communicate with the electronic memory of theat least one patch to obtain the threshold data corresponding to thedose amount of radiation exposure the at least one sensor patch isexposed to during the administering of therapeutic radiation.
 71. Thereader of claim 68 wherein the reader is further configured toautomatically prompt the user of the reader for predetermined databefore determining the radiation dose; then automatically determine theradiation dose using the predetermined data.
 72. The reader of claim 71wherein the predetermined data comprises a correction factor related tothe at least one sensor patch.
 73. The reader of claim 68 wherein theelectronic memory further comprises detected and/or calculated radiationdoses, date and/or time stamps, and/or a clinician entered patientidentifier and/or record number.
 74. An external radiation dosimetertest strip, the test strip comprising a substrate holding a circuitincluding a resistor and a voltage reference configured to provide apredetermined output when read by a calibrated dose reader.
 75. The teststrip of claim 74 wherein the circuit further comprises a test stripelectronic memory configured to store a predetermined reference voltage.76. The test strip of claim 75 wherein the test strip is adapted to bereceived by the dose reader so as to allow the dose reader to obtain thepredetermined reference voltage.
 77. The test strip of claim 75 whereinthe test strip is configured to electrically contact the dose reader soas to allow the dose reader to obtain the predetermined referencevoltage.
 78. The test strip of claim 75 wherein the test strip isconfigured to wirelessly communicate with the dose reader so as to allowthe dose reader to obtain the predetermined reference voltage
 79. Thetest strip of claim 74 wherein the voltage reference comprises a 1.2 Vshunt and wherein the resistor comprises a 10 KΩ resistor.
 80. A systemfor testing the functionality of a dose reader, the system comprising:an external radiation dosimeter test strip including a substrate holdinga circuit including a resistor and a voltage reference; and a dosereader configured to communicate with the test strip and obtain apredetermined reference voltage.
 81. The system of claim 80 wherein thecircuit further comprises a test strip electronic memory configured tostore the predetermined reference voltage.
 82. The system of claim 80wherein the test strip is adapted to be received by the dose reader soas to allow the dose reader to obtain the predetermined referencevoltage.
 83. The system of claim 80 wherein the test strip is configuredelectrically contact the dose reader so as to allow the dose reader toobtain the predetermined reference voltage.
 84. The system of claim 80wherein the test strip is configured to wirelessly communicate with thedose reader so as to allow the dose reader to obtain the predeterminedreference voltage
 85. The system of claim 80 wherein the voltagereference comprises a 1.2 V shunt and wherein the resistor comprises a10 KΩ resistor.
 86. The system of claim 80 wherein the dose reader isfurther configured to provide an output to indicate that the dose readeris calibrated correctly if the predetermined reference voltage is in apredetermined range and to provide an output to indicate that the dosereader is not calibrated correctly if the reference voltage is not inthe predetermined range.
 87. The system of claim 86 wherein thepredetermined range is from about 4.075 V to about 4.116 V.